This file summarizes all changes made to Tk since version 1.0 was
released on March 13, 1991.  Changes that aren't backward compatible
are marked specially.

sccsid = @(#) changes 1.21 95/06/30 11:18:48

3/16/91 (bug fix) Modified tkWindow.c to remove Tk's Tcl commands from
the interpreter when the main window is deleted (otherwise there will
be dangling pointers to the non-existent window).

3/16/91 (bug fix) Modified tkColor.c not to free black or white colors:
some X servers get upset at this.

3/18/91 (bug fix) Modified tkShare.c to fix bug causing "DeleteGroup
couldn't find group on shareList" panic.

3/18/91 (bug fix) Several changes to tkListbox.c and tkScrollbar.c to
handle listboxes (and scrollbars) with zero total entries in them.

3/22/91 (bug fix) Fixed a few ='s in tkListbox.c that should be ==.

3/22/91 (bug fix) Fixed error in main.c that caused BadWindow errors
in some cases where wish scripts invoke "destroy .".

3/23/91 (new feature) Added Tk_CancelIdleCall to remove Tk_DoWhenIdle
handler.

3/23/91 (bug fix and new feature) Added -name option to main.c, made
it more clever about choosing name (was always using the name "wish"
on most Unix systems).

3/23/91 (new feature) Added TK_CONFIG_STRING option to Tk_ConfigureWidget,
used it to malloc strings for various widget options that used to be
Tk_Uid's (e.g. button text, message strings, etc.).  Eliminates core
leaks when values change in continuous non-repeating fashion.

3/29/91 (new feature) Added Tk_Preserve, Tk_Release, and
Tk_EventuallyFree procedures to help manage widget records and avoid
premature memory free-ing.

4/4/91 (bug fix) Fixed problem in tkWm.c where top-level window geometry
wasn't tracking correctly when wm-induced size change also changed window
position (e.g. menus wouldn't be displayed at the right places).

4/5/91 (new feature) Added "invoke" option to widget command for buttons,
check buttons, and radio buttons.

4/5/91 (new feature) Added "unpack" option to "pack" command.

4/5/91 (bug fix) Changed tkPack.c to use new Tk_Preserve code and be
more careful about window deletions that occur while repacking is in
progress.

4/6/91 (bug fix) Major overhaul of deletion code in all widgets to use
Tk_Preserve and Tk_Release.  Should fix many problems.

4/6/91 (bug fix) Changed "winfo children" to generate correct lists
when child names have embedded spaces.

4/6/91 (new feature) Added "screenheight" and "screenwidth" options to
"winfo".

4/18/91 (bug fix) Binding mechanism didn't correctly handle very long
%-substitutions in commands (e.g. long path names) and caused memory
to be overwritten.  Modified tkBind.c to fix.

---------------------- Release 1.1, 4/18/91 -------------------------

4/19/91 (bug fix) Inconsistent ICCCM handling of coordinates of reparented
windows causes windows to gradually walk south when moved or resized.
Fixed tkWm.c to patch around the problem.

---------------------- Release 1.2, 4/24/91 -------------------------

4/26/91 (new feature) Added -geometry and -display switches to wish.
Also wrote wish manual entry.

5/3/91 (bug fix) Fixed bug in tkListbox.c that caused garbage to appear
at right edge of window when strings were to large to fit in window.

5/3/91 (bug fix) Fixed bug in tkListbox.c where topIndex wasn't getting
updated when elements were deleted:  tended to cause errors in
communication with scrollbars.

5/16/91 (bug fix) Fixed bug in tk3d.c, which caused core dumps when
consecutive points in a polygon were the same (happened with some
configurations of radio buttons, for example).

5/16/91 (bug fix) Fixed main.c to allow stdin to be redirected.

6/1/91 (bug fix) Make sure that pointers are never used after being
freed.

6/15/91 (bug fix) Fixed bug in tkBind.c that caused current binding
values to not always be printed correctly.

6/15/91 (bug fix) Make sure that interpreters are always unregistered
when their main windows are deleted, and make wish delete the main
window before exiting.

8/21/91 (misfeature correction)  Automatically set source of window
position to "user" in "wm geometry" command, unless it has been
explicitly set to "program".

9/5/91 (bug fix) Modified option code to accept '#' as a comment
character in .Xdefaults files, in addition to '!'.

9/10/91 (misfeature correction) Changed binding mechanism so that
numeric %-sequences are output in decimal instead of hex.

9/19/91 (bug fix) Fixed bug in Tk_DoOneEvent(1) where it wasn't
checking files and X connections properly so it missed events.

10/6/91 (new feature) Reorganized tkBind.c to provide generic "binding
table" structure, which can be used to create bindings on items in
canvases as well as windows.

10/6/91 (new feature) Upgraded buttons and menus to use new tracing
code in Tcl 6.0.  Allows radio buttons and check buttons to both set
and clear themselves when associated variable changes.

10/17/91 (bug fix) Fixed 2 bugs in listboxes: accidentally advanced the
selection when new entries were inserted in the listbox after the location
of the selected item(s), and goofed up on redisplay if selected item
was deleted and then selection was immediately lost.

10/27/91 (bug fix) "pack unpack" wasn't telling Tk that it no longer
manages window;  this led to core dumps in some situations.

10/31/91 (reorganization) Renamed manual entries so that they are no
more than 14 characters in length.

10/31/91 (reorganization) Changed tk.h and tkInt.h so that tkInt.h
doesn't needed to be included by tk.h.

11/3/91 (portability improvement) Eliminated use of "class" as a variable
name, since it's a reserved word in C++.

11/7/91 (reorganization) Many changes to upgrade for Tcl 6.1 including
use of Tcl hash tables instead of separate "Hash_" module.  The "lib"
subdirectory is no longer needed in Tk.

---------------------- Release 1.3, 11/7/91 -------------------------

11/24/91 (bug fix) Fixed bug causing occasional errors if existing bindings
are modified (FindSequence in tkBind.c forget to set *maskPtr).

11/24/91 (bug fix) Used wrong hash table in Tk_GetColorByValue.  Could
cause new entries to get created unnecessarily.

12/2/91 (bug fix) Changed "bind" code to put backslashes in front of
special characters (e.g. [ or \) that appear in %-replacements, so that
they can be parsed cleanly.

12/10/91 (bug fix) Manual entries had first lines that caused "man" program
to try weird preprocessor.  Added blank comment lines to fix problem.

1/2/92 (documentation cleanup) Changed manual entries for Tk_GetBitmap
and the like to make it more clear that the argument must be a Tk_Uid
and not a string.

1/2/92 (bug fix) Fixed problem where scrollbars that were very short or
very narrow (too small to hold both arrows) could cause negative values
in calls to XClearArea, which crashed some servers.

1/2/92 (bug fix) Fixed bug in TkMeasureChars occurring when maxChars
is 0.  Occasionally affected things like message window geometry.

1/3/92 (new feature) Added procedures Tk_GetJustify, Tk_GetAnchor,
Tk_GetCapStyle, and Tk_GetJoinStyle, plus support for these things
in Tk_ConfigureWidget.

---------------------- Release 1.4, 1/10/92 -------------------------

1/12/92 (bug fix) TkMenubutton.c wasn't cleaning up mbPtr->varName
properly during menubutton cleanup if an error occurred during
menubutton creation.

1/19/92 (bug fix) Fixed off-by-one bug in tkListbox.c that caused
scrollbars to display a slider that was too large.

2/10/92 (bug fix) Tk_CreateFileHandler didn't correctly handle case
where new mask was specified for existing handler.

2/13/92 (bug fix) Tk_DeleteAllBindings wasn't correctly removing
bindings from the pattern table:  only did the removal for the
first pattern in a pattern list.

2/15/92 (new feature) Added procedures Tk_DefineBitmap and
Tk_SizeOfBitmap.  Tk_GetBitmapFromData is now considered obsolete
and probably shouldn't be used anymore.  Tk_GetBitmapFromData
is now implemented by calling Tk_DefineBitmap and Tk_GetBitmap.

2/15/92 (new feature) Added "curselection" and "select clear" options
to widget command for listboxes.

2/15/92 (new feature) Added Tk_3DBorderColor procedure.

2/17/92 (relaxed limitations) Changed scrollbars so they no longer limit
the slider position to lie within the object's range:  can scroll off the
end of an object, if the object permits it.  Changed listboxes and
entries to explicitly prevent viewing off the ends.  Also relaxed
listbox index checks so that out-of-range indices are automatically
adjust to fit within the listbox range.

2/19/92 (bug fix) tkWindow.c tended to leave half-created windows around
if a new window's name was found to be in use already.  Fixed to clean
them up.

2/22/92 (new feature) Added -anchor, -bitmap, -height, -textvariable,
-width options to labels, buttons, check buttons, menu buttons, and radio
buttons.  This means that (a) size can be controlled better, (b) bitmaps
can be displayed in any buttons, (c) the position of the text within the
button can be controlled, and (d) a button can be made to display the value
of a variable, continuously updating itself.  Also changed -selector option
so that if it's specified as an empty string then no selector is drawn
for the button.

2/22/92 (new feature) Changed menus to support bitmaps in menu entries:
added new -bitmap option for entries.

2/26/92 (bug fix) "after" command, when invoked with just one argument,
called Tk_Sleep rather than registering a timer handler and looping on
Tk_DoOneEvent.  As a result, it caused the application to become non-
responsive to X events during the sleep.  Changed to use a Tk_DoOneEvent
loop so that it is responsive.

2/26/92 (bug fix) Tk's main program didn't map the main window until
after the startup script returned.  Changed to map the window as a
do-when-idle handler, so that scripts can cause the window to be
mapped immediately with a call to "update" or "after".

2/28/92 (bug fix) "wm withdraw" wasn't working if invoked before window
was originally mapped:  window got mapped anyway.  Fixed so that the
window doesn't get mapped as long as it's withdrawn.

2/29/92 (new feature) Can use "focus none" to clear input focus.

2/29/92 (bug fix) Fixed tkEvent.c to generate SubstructureNotify events
properly.  These weren't being generated previously.

2/29/92 (bug fix) Fixed entries so that newline characters can be properly
displayed (as `\x0a').  Had to change interface to TkDisplayChars in order
to do this (added flags argument).

2/29/92 (bug fix) Change Tk not to update size and position of top-level
windows directly during calls like Tk_ResizeWindow.  Instead, wait until
actual event is received.  This makes updates happen at same time as
callbacks.

3/6/92 (bug fix) TkMenubutton.c was dumping core when a menubutton was
pressed at a time when there was no associated menu for the button.

3/6/92 (new feature) Added Tk script library directory with official
Tk initialization file "tk.tcl".  Other procedures used by Tk are in
other files.  Tk procedures and variables all have names starting
with "tk_".  Also added Wish startup script "wish.tcl", which sources
both the Tk and Tcl startup scripts.  This means that things like
auto-loading and abbreviation expansion are now available in wish.
Added new variables tk_library, tk_priv, and tk_version.

3/6/92 (new feature) It's now possible to set bindings for whole
classes by using the class name in the bind command.  For example,
"bind Button <Enter> {puts stdout Hi!}" will cause a message to be
printed whenever any mouse button is entered.  Can also use "all"
to set bindings for all widgets.  Widget-specific bindings override
class bindings which override "all" bindings.

3/6/92 (reorganization) Changed buttons (all flavors) and listboxes to
eliminate all hard-wired behavior.  Instead, default behavior is set
by class bindings in tk.tcl.  Also set up class bindings for menus,
menubuttons, and entries, which previously had no default behavior at
all.  Scrollbars and scales still have hard-wired behavior that can't
be overridden.

3/7/92 (look-and-feel change) Changed listboxes and entries and menus
to use button 2 for scanning instead of button 3.  This is more consistent
with the official Motif use of button 2 for dragging.

3/10/92 (new features) Added more options to "winfo" command:  screencells,
screendepth, screenmmheight, screenmmwidth, and screenvisual.

3/13/92 (bug fix) Event sharing mechanism (tkShare.c) wasn't checking
to see whether window was mapped before sharing events with it.

3/16/92 (bug fix) Tk_SetInternalBorderWidth was passing wrong window to
geometry-management procedures, causing core-dumps when menu buttons
had their border widths changed.

3/16/92 (bug fix) Menus were setting their geometry directory rather
than using Tk_GeometryRequest mechanism.

3/17/92 (new feature) Added -cursor option to all widgets to set the
active cursor for the widget.  Also added TK_CONFIG_ACTIVE_CURSOR
configure type.

3/18/92 (new feature) Implemented generalized screen coordinates to
allow resolution-independent specification in many cases (but pixel-
based coordinates are still OK).  Added Tk_GetScreenMM(),
Tk_GetPixels(), new configure types TK_CONFIG_SCREEN_MM and
TK_CONFIG_PIXELS.  Changed widgets to use this new configure types
wherever possible (a few of the more complex cases still haven't
been taken care of yet).  Added "pixels" and "fpixels" options to
"winfo" command.

3/18/92 (new feature) First cut at canvas widgets is done and part of
the official Tk now.  Canvases display text and structured graphics,
and allow you to bind commands to events related to the text and
graphics.

3/21/92 (new feature) Added new "place" command.  It implements a
new geometry manager that provides fixed placement, rubber-sheet
placement, and combinations of the two.  Eliminated the commands
"move", "resize", and "map" that were provided by main.c but never
officially supported;  the placer provides all of this functionality.

3/23/92 (bug fix) Fixed bug in tkWm.c where top-level windows were
occasionally not being given the right size.  The problem occurred
when a string of resizes happened all in a row (such as deleting all
the windows in an application and then recreating them).

3/23/92 (new feature) Added Tk_CoordsToWindow procedure and
"winfo containing" command.  These may be used to locate the window
containing a given point.

3/28/92 (new feature) Added "-exportselection" option to listboxes,
so that listbox selection need not necessarily be the X selection.

4/12/92 (bug fix) Changed menu buttons to store name of menubutton
in the associated variable, rather than the name of the menu.  This
is necessary in order to allow several menu buttons to share the
same menu.
*** POTENTIAL INCOMPATIBILITY ***

4/12/92 (bug fix) Fixed core dump that occurred in tkError.c when
removing the first error record from the error list.

4/15/92 (bug fix) Fixed bug in tkBind.c that prevented <KeyPress-1>
event specifications from being processed correctly:  the "1" was
treated as a button name rather than a keysym.

4/18/92 (new feature) Added Tk_DefineCursor and Tk_UndefineCursor
procedures.

4/18/92 (new feature) Major revision to listboxes.  Can now scroll and
scan in both x and y, plus -exportselection option allows selection not
to be exported.  The "view" widget command has been replaced by "xview"
and "yview", and the "scan" widget command has a new syntax.
*** POTENTIAL INCOMPATIBILITY ***

4/18/92 (new feature) Added -exportselection option to entries, so you
can select whether you want the entry selection to be the X selection
or not.

4/24/92 (new features) Added TK_CONFIG_CUSTOM type to Tk_ConfigureWidget,
plus added new flags TK_CONFIG_NULL_OK, TK_CONFIG_DONT_SET_DEFAULT,
and TK_CONFIG_OPTION_SPECIFIED.  Several other new types, such as
TK_CONFIG_CAP_STYLE, were also added as part of implementing canvases.

4/29/92 (bug fix) Changed "-selector" default for menus to have separate
values for mono and color.

4/30/92 (bug fix) Fixed bug in tkListbox.c where it occasionally generated
bogus scroll commands (last index less than first).

4/30/92 (reorganization) Moved demos directory to "library/demos".

---------------------- Release 2.0, 5/1/92 -------------------------

5/2/92 (bug fix) Fixed problem in tkListbox.c where it was doing too many
redisplays after repeated insertions.  Also reduced number of invocations
of scrollbar commands.

5/7/92 (portability improvement) Changed main.c not to use TK_EXCEPTION
flag;  it isn't needed and it causes problems on some systems.

5/9/92 (bug fix) Plugged core leaks in tkListbox.c and tkBind.c

5/9/92 (bug fix) TkBind.c was accidentally deleting bindings during
attempts to print non-existent bindings.

5/11/92 (bug fix) Maximum name length for applications (name used in
"send" commands) was too short (only 20);  increased to 1000.  Also
fixed bug related to over-long names that caused core dumps.

5/13/92 (bug fix) tkShare.c was using a dangling pointer if a share
group was deleted as a side-effect of a shared event.

5/13/92 (bug fix) Various initialization and core leak problems in
tkGC.c, tkSend.c, tkMenu.c, tkEvent.c, tkCanvas.c, tkCanvPoly.c,
tkCanvLine.c, tkListbox.c, tkEntry.c.

5/13/92 (bug fix) Empty entries could be scanned off the left edge,
displaying a garbage character.

5/13/92 (bug fix) Fixed a few problems with window manager interactions,
such as tendency for windows to spontaneously shrink in size.  By no
means are all of the problems fixed, though.

5/13/92 (performance optimization) Changed Tk_GeometryRequest not to
invoke geometry manager unless requested size has changed.

---------------------- Release 2.1, 5/14/92 -------------------------

5/1/92 (new features) Added flags like TK_IDLE_EVENTS to Tk_DoWhenIdle,
plus added "idletasks" option to "update" command.  Tk_DoWhenIdle arguments
look different now, but the change should be upward-compatible.

5/17/92 (new feature/bug fix) Added support for VisibilityNotify events
to the "bind" command.  For some reason they weren't supported previously.

5/17/92 (new feature) Added "tkwait" command.

5/17/92 (new feature) Added "grab" command.

5/17/92 (new feature) Added "-width" option to messages.  Also changed
messages to use the computed (i.e. desired) line length when displaying,
not the actual width of the window.

5/17/92 (bug fixes) Did some more fiddling with tkWm.c in the hopes
of improving window manager interactions.  Now there won't be more than
one configure request outstanding to the wm at a time.

5/17/92 (bug fix) Arrowheads on canvas lines weren't being translated
or scaled correctly.

5/20/92 (bug fix) Page-mode scrolling didn't work correctly for canvases
(wrong windowUnits was passed to scrollbars).

5/20/92 (bug fix) Changed scrollbars not to lose highlight when pointer
leaves window with button down.  Also changed redisplay to double-buffer
for smoother redraws.

5/21/92 (new feature) Added "gray50" and "gray25" as predefined bitmaps.

5/22/92 (new feature) Buttons can now be disabled using the "-state" and
"-disabledforeground configuration options.  The "activate" and "deactivate"
widget commands for buttons are now obsolete and will go away soon.
Please change Tcl scripts not to use them.

5/23/92 (new feature) Entries can now be disabled using the "-state"
config option.  Also improved class bindings for entries to keep the
cursor visible in the window when operations occur.  Also made slight
improvements in the way redisplay is done.

5/23/92 (new feature) Added "-textvariable" option to entries so that
the text in an entry can be tied to the value of a global variable in
a fashion similar to buttons.

5/27/92 (new feature) Added "-textvariable" and "-anchor" options to
messages.

5/28/92 (new feature) Added "-padx" and "-pady" and "-underline" options
to menubuttons.

5/28/92 (feature change) Changed "-width" and "-height" options on
all flavors of buttons and menubuttons so that they are orthogonal
to "-padx" and "-pady".  It used to be that -width overrode -padx
(no padding).  Now they accumulate.

5/29/92 (new feature) Added "-disabledforeground" option to menus and
all flavors of buttons (can specify color for disabled things rather
than just using stipple to gray out).

5/29/92 (new features) Added many new options to menu entries:
-activebackground, -background, -font, -state, -underline.  The
"disable" and "enable" widget commands for menus are now obsolete
and will go away soon.  Please change Tcl scripts not to use them.

5/29/92 (new features) Added "atom" and "atomname" options to "winfo"
command.

5/29/92 (new feature) Wrote tk_listboxSingleSelect procedure, which
can be used to change listbox behavior so that only a single item is
selected at once.

6/1/92 (new feature) Added new modifier names "Meta" and "Alt" for
"bind" command.

6/3/92 (new feature) Added "winfo toplevel" command.

6/3/92 (new feature) Made several changes for greater Motif compliance,
including:
    - menu retention if you click and release in the menu button,
    - keyboard traversal of menus (see traversal.man)
    - no widget flashing if you set $tk_strictMotif to 1

6/15/92 (bug fix) Fixed problem in tkBind.c where command string for a
binding could get reallocated while the command was being executed (e.g.
bindings that delete or change themselves).

6/15/92 (bug fix) Don't allow "tabWidth" field to become zero in tkFont.c:
can cause core dumps for fonts that don't enough information to compute
tab widths.

6/19/92 (bug fix) Fixed bug in binding mechanism that caused structure-
related events to be reported both to the correct window and its parent.

7/14/92 (bug fix) Changed tkColor.c not to free colors for visual types
StaticGray or StaticColor.

7/15/92 (new feature) Text widgets now exist.  They display any number of
lines of text with a variety of display formats, and include hypertext
facilities.  See the manual page for details.

7/20/92 (bug fix) If a top-level window was put in the iconic state to
begin with, it could be deiconified with "wm deiconify .foo" until it had
first been deiconified by hand from the window manager.  Tk was getting
confused and thought the window was mapped when it wasn't.

7/29/92 (bug fix) Don't permit rectangles or ovals to have zero-sized
dimensions.  Round up to at least one pixel.

7/29/92 (new features) Major upgrade to canvases:
    - new item types: arc, window, bitmap
    - added Bezier spline support for lines and polygons
    - rectangles and ovals now center their outlines on the shape,
      rather than drawing them entirely inside the shape
    - new "coords" and "bbox" widget commands
    - new "-tags" option for all item types.
    - new "-confine" option to prevent scrolling off edge of canvas.

8/6/92 (new feature) Added "-width" and "-height" options to frames.
The "-geometry" option is now obsolete and should be removed from Tcl
scripts:  it may go away in the future.

8/7/92 (bug fix) Error messages in Tk_ParseArgv were sometimes including
the option name where they should have included its value.

---------------------- Release 2.2, 8/7/92 -------------------------

8/7/92 (bug fix) Changed tkCanvas.c to be more conservative in the area
it passes to XCopyArea.

8/8/92 (bug fix) Fixed bug in tkTextDisp.c that sometimes caused core
dumps when text views changed (e.g. typing return on last line of screen).

8/8/92 (bug fix) Fixed bug in menu.tcl that caused errors when using
keyboard to traverse over separator menu entries.

8/10/92 (bug fix) Changed to use OPEN_MAX instead of MAX_FD to compute
maximum # of open files.

8/10/92 (bug fix) Canvases weren't updating scrollbars on window size
changes.  They also weren't recentering canvases on window size changes.

8/10/92 (bug fix) There were still a few places where commands were being
invoked at local level instead of global level (e.g. commands associated
with buttons and menu entries).

8/10/92 (bug fix) TkBind.c used to ignore explicit shift modifiers for
all keys (i.e. <Shift-Tab> was treated the same as <Tab>).  Modified to
allow explicit request for shift modifier, like <Shift-Tab>.

8/13/92 (feature change) Changed default fonts to request "Adobe" fonts
explicitly.

8/16/92 (bug fixes) Modified tkCanvArc.c and tkTrig.c to increase slightly
the bounding boxes for arcs, in order to make sure that proper redisplay
occurs when arcs are moved (little turds were getting left behind).

8/16/92 (bug fix) Modified tkCanvas.c not to redraw at all if the redisplay
area is off the screen.  Also, only do a background clear for the portion
of the redraw area that is on-screen.  Also, reduced size of off-screen
pixmaps used for redisplaying, which speeds up redisplay in some cases.

8/19/92 (bug fix) Canvases that were taller than wide were not being
redisplayed properly.

8/20/92 (new feature) Added Tk_CreateGenericHandler procedure for trapping
all X events (useful for tracing, watching non-Tk windows, etc.).

8/21/92 (bug fix) Widgets weren't always being notified when they got
the focus back again (the problem had to do with grabs and menus in
particular).

8/21/92 (new feature) Added "-state" option to scale widgets.

8/22/92 (new feature) Changed tkBitmap.c to allow tilde-substitution
to occur in bitmap file names.

---------------------- Release 2.3, 8/24/92 -------------------------

8/27/92 (bug fix) Changes to -activebackground and -activeforeground options
for menubuttons were being lost.

8/27/92 (bug fix) Entries were selecting last character when a B1-drag
occurred past the right edge of the text.

8/28/92 (bug fix) Fixed bug in canvases where a grab during a button
press caused the canvas state to lock up so that it didn't select a
new current item.

9/7/92 (bug fix) Changed tkMenu.c to accept numerical menu indices that
are out of range;  now it just rounds them off to the nearest existing
entry.

9/7/92 (bug fix) Fixed bug in tkTextDisp.c that caused core dumps when
invoking "yview -pickplace" widget command on texts that are too small
to hold any lines at all.

9/11/92 (bug fix) Fixed bug in tkTextDisp.c that caused core dumps
when adding tags to non-existent lines.

9/11/92 (bug fix) Line items in canvases didn't permit an empty fill
color (i.e. couldn't make them transparent).

9/14/92 (reorganization) Changed manual entries to use .1, .3, and .n
extensions.  Added "install" target to Makefile to suggest how Tk should
be installed.

9/16/92 (bug fix) Changed tkSend.c to always specify the root window of
screen 0 rather than using DefaultRootWindow.  DefaultRootWindow doesn't
always go to screen 0 on displays with multiple screens, which can result
in send's not being possible between the screens.

9/18/92 (new feature) Added three new options to "wm" command: "protocol",
"client", and "command".  These provide support for window manager protocols
such as WM_DELETE_WINDOW and WM_TAKE_FOCUS, plus support for the
WM_CLIENT_MACHINE and WM_COMMAND properties.

9/30/92 (new feature) Implemented color model support, including
"tk colormodel" command and Tk_GetColorModel and Tk_SetColorModel
procedures.  These allow you to force mono operation even on a color
display.  Also changed color allocation not to give errors when colors
run out, but just to switch to a mono color model.

10/1/92 (bug fixes) Fixed two bugs in tkTextBTree.c that caused core dumps
during text deletion.

10/5/92 (bug work-around) Changed tkColor.c to ignore errors when freeing
colors.  This is needed to work around improper reference count management
for colormap entries under X11/NeWS.

10/7/92 (new feature) Added support for different visual types, including
procedures Tk_SetWindowVisual and Tk_SetWindowColormap, plus macros
Tk_Visual, Tk_Depth, and Tk_Colormap.  The code for this was contributed
by Paul Mackerras.

10/7/92 (new feature) Added Tk_IsTopLevel macro.

10/12/92 (bug fix) Fixed bug in tk.tcl that caused torn-off menus with
cascaded children not to track mouse motion correctly (the cascade
switched in response to mouse motions within the cascaded child).

10/12/92 (new feature) Major changes to focus handling:
(a) Tk watches FocusIn and FocusOut events for focus changes, not Enter
    and Leave, so it will work better with explicit-focus-model window
    managers (e.g. mwm in default mode).
(b) Tk generates FocusIn and FocusOut events for the focus window now.
    The old procedural interface (via Tk_CreateFocusHandler) is obsolete
    and is no longer used inside Tk.  It is still supported for
    compatibility, but won't be for long.  You should change your code
    to use FocusIn and FocusOut events instead.
(c) The model for FocusIn and FocusOut events is different than the
    one described in Xlib documentation.  See the "focus" manual entry
    for details.
(d) If there is no input focus then keyboard events are discarded.  They
    used to be directed to the mouse pointer window, although this wasn't
    documented.  The focus now defaults to the root window.
*** POTENTIAL INCOMPATIBILITY ***

10/15/92 (bug fix) Fixed text items in canvases where they didn't
display the insertion cursor if the item had no characters in it.

10/26/92 (bug fix) Fixed bug in tkSelect.c that occasionally caused
BadWindow X protocol errors when retrieving the selection.  Tk wasn't
making sure that a window existed before using it to retrieve the
selection.

10/30/92 (feature change) Changed canvases so that if the scroll region
is smaller than the window and -confine is on, the scroll region isn't
forced to be centered in the window;  it can be anywhere that meets the
confinement restrictions.

11/2/92 (new feature) Added "winfo exists" command.

11/5/92 (new feature) Changed DoWhenIdle handlers so that if a new
when-idle handler is created as a side-effect of another when-idle
handler, the new handler isn't invoked until Tk has first checked
for other events to process.

11/6/92 (bug fixes, new features) Major overhaul of window manager
interface:
(a) Tk should now work with virtual-root window managers;
(b) windows will now place more accurately on the screen and stay where
    they're supposed to;
(c) size changes handled more reliably;
(d) code now works robustly in the face of withdrawals followed
    immediately by deiconifications.
(e) Added new procedure Tk_GetVRootInfo and new options to "winfo" command:
    vrootx, vrooty, vrootwidth, vrootheight.
(f) Added "overrideredirect" option to "wm".
(g) Fixed bug where change in width-only via "wm geom" didn't always work
   (min and max window sizes weren't being set properly for the wm).

11/6/92 (bug fixes) Modified menus so that they work correctly with
virtual root window managers.  Also fixed bug where menus didn't move
along with their associated windows, so that the menu popped up at
the old location of the window rather than its new location.

11/9/92 (new constraint) Made it illegal to give windows names that
start with upper-case letters, since such names will goof up the
option database by appearing to be classes rather than names.
*** POTENTIAL INCOMPATIBILITY ***

11/10/92 (new feature) Added Postscript output to canvases.

11/13/92 (bug fix) Changed default for maximum size passed to window
manager from 1000000 (which causes some wm's to make windows too large
when "maximized") to the size of the display.

11/14/92 (feature change) Major overhaul of menubuttons and pull-down
menus.  Removed event-sharing code, including Tk_ShareEvents and
Tk_UnshareEvents.  The -variable option for menubuttons has been
removed,and the "post" and "unpost" widget commands for menubuttons
no longer exist.  The "post" widget command for menus no longer
allows a group option.  The procedure tk_menus has been replaced
with a new procedure, tk_menuBar, which has a slightly different
interface.
*** POTENTIAL INCOMPATIBILITY ***

11/20/92 (new features, feature changes) Major overhaul of grab
mechanism to produce more correct event streams.  Also changed Tcl
commands to require explicit window for grab releases (makes it
possible for grabs to work on multiple displays simultaneously).
The old "grab none" command no longer exists, but new options
have been added: "current", "release", "set", and "status".
*** POTENTIAL INCOMPATIBILITY ***

11/20/92 (new feature) Use TK_LIBRARY environment variable to set library
directory location, if it is defined.  Otherwise fall back on usual
compiled-in value.

11/25/92 (bug fix) "wm grid" command was using wrong window.

11/29/92 (bug fix) Fixed core dump that occurred when trying to use
placer on top-level windows: return error instead.

11/29/92 (bug fix) Selection retrieval wasn't making sure that the window
on whose behalf selection is being retrieved actually exists.

12/3/92 (new feature) Added support for Mode_switch key to support the
full ISO character set.  Also added event handlers for MappingNotify
events so that Tk updates itself in response to keycode and modifier
changes.

12/6/92 (bug fix) Ignore recursive attempts to destroy window.

12/9/92 (new demos) Added "tcolor" and "rmt" demos.

12/10/92 (new features) Added "yposition" widget command for menus,
changed "delete" widget command to take an optional second index,
and changed -command option for cascade entries so that it is
invoked when the entry is activated rather than when it is invoked.
*** POTENTIAL INCOMPATIBILITY ***

12/12/92 (implementation change)  Changed the procedures Tk_FreeBitmap,
Tk_NameOfBitmap, Tk_SizeOfBitmap, Tk_FreeCursor, Tk_NameOfCursor, and
Tk_FreeGC to require an addition Display argument.  This is needed for
Tk to function correctly when an application has windows on multiple
displays.
*** POTENTIAL INCOMPATIBILITY ***

12/12/92 (new feature) Started creating a test suite.  Right now it
only has a few tests.

12/12/92 (new feature) Modified the packer so that a window can be
packed in descendants of its parent (used to be restricted to the
parent alone).  This makes it possible to hide extra windows used
for geometry management.  Also, can use generalized screen distances
in the "pack" command.

12/16/92 (feature change) Boolean options such as -exportselection now
print as 0/1 rather than true/false (both the default and current values
print this way).  This makes it easier to use these values in expressions.
*** POTENTIAL INCOMPATIBILITY ***

12/16/92 (name change) The classes "RadioButton" and "CheckButton" have
been renamed "Radiobutton" and "Checkbutton" for consistency.  From now
on widget class names will have exactly one capital letter.
*** POTENTIAL INCOMPATIBILITY ***

12/16/92 (new feature) Added -setgrid option to listboxes.

12/16/92 (new feature) The "destroy" command, and the "delete" widget
command for canvases, now accept any number of arguments, including
zero.

12/16/92 (new feature) Changed internal TkBindError procedure to
Tk_BackgroundError and exported it to Tk clients.

12/16/92 (option name change) Changed the place command's "dependents"
option to "slaves" for better consistency with documentation.
*** POTENTIAL INCOMPATIBILITY ***

12/16/92 (name changes) Renamed the "cursor*" options in entries and
canvases to "insert*".  Also renamed the "cursor" index to "insert" and
the "cursor" widget command to "icursor".  This was done to avoid
confusion between the mouse cursor and the insertion cursor.
*** POTENTIAL INCOMPATIBILITY ***

---------------------- Release 3.0, 12/17/92 -------------------------

12/17/92 (bug fix) Fixed dangling-pointer bug in canvases that occurred
if a <LeaveNotify> binding deleted the current item.

12/18/92 (bug fix) Core dump occurred if "wm" invoked with no arguments.
Also, tkWm.c wasn't properly setting WM_CLASS property on application
startup.

12/18/92 (incorrect documentation) Updated manual entries for Tk_FreeGC,
Tk_FreeCursor, and Tk_FreeBitmap to reflect new interface that requires
"display" argument.

12/18/92 (missing documentation) Added documentation for the canvas
"postscript" command, which was missing in the 3.0 release.

12/21/92 (bug fixes) There were lots of problems with the new installation
targets in the Makefiles, such as using "cp -f" and not installing
prolog.ps.  Made several other miscellaneous improvements to Makefile.

12/21/92 (bug fix) Arrowheads on canvas line items weren't moving properly
after coordinate changes made with the "coords" widget command.

12/21/92 (bug fix) If top-level window was initially withdrawn, couldn't
ever deiconify it again.

12/21/92 (bug fix) Double-button event sequences didn't always trigger
properly when grabs were in effect.

12/22/92 (bug fix) The packer didn't display any top or bottom windows
after a left or right expanded window, and vice versa.  Also made the
distribution of space among expanded windows more even.

12/28/92 (new features) Several improvements to selection:
(a) Added procedures Tk_ClearSelection and Tk_DeleteSelHandler.
(b) Added "clear" and "own" options to "selection" command, extended
    "handle" option to delete handlers.
(c) Error returns from "selection handle" scripts are now turned into
    selection retrieval errors ("no such selection") rather than an
    empty selection.
(d) Tk responds automatically for targets APPLICATION (name of application,
    so you can "send" to it) and WINDOW_NAME (name of window within
    application.
(e) Added test file "select.test" to test suite.

12/28/92 (bug fix) Fixed problem with flashing menus that occurred
because menu.tcl was willing to unpost and then immediately repost
the same menu.

1/6/93 (bug fix) Test for UnmapNotify events in tkPack.c used = instead
of ==.

1/21/93 (bug fix) Changed many widgets to eliminate use of
DefaultVisualofScreen, DefaultColormap, etc. and use the visuals
and colormaps for the actual windows instead.  Also changed to
inherit colormaps and windows from parent by default.

1/21/93 (new features) Added new winfo options "cells", "depth", and
"visual".

1/23/93 (bug fix) Fixed problem with text display that could result
in negative XCopyArea heights being sent to X server.  This causes some
servers (e.g. some versions of OpenWindows) to crash.

1/25/93 (new feature) Added -postcommand option to menus, so that menus
can be reconfigured before each posting.

1/29/93 (feature change) Changed %X and %Y in bindings so that they
refer to the virtual root rather than the true root.  Although
potentially incompatible, this change should almost always "do the
right thing".
*** POTENTIAL INCOMPATIBILITY ***

1/31/93 (bug fix) Changed "send" code to grab server while updating
the registry property (before this fix, two programs could allocate
the same interpreter name if they started up simultaneously).  In
order to make this fix I had to change the code for reclaiming
names of dead interpreters in a way that sometimes allows dead
interpreters to persist in the registry.

2/1/93 (feature change) Changed entries to allow leftmost "visible"
character to be the end of the text (i.e. no characters actually visible).
This is needed so that the cursor can be displayed even if the last
actual character is too wide to fit in the window.

2/3/93 (bug fix) Fixed two bugs in tkFocus.c:  (a) FocusIn events
were getting lost in some cases because the focus window hadn't been
created yet (e.g. new top-level window pops up underneath the mouse);
(b) Tk was accidentally triggering FocusOut events when the mouse
moved from a top-level window to one of its children.

2/4/93 (new feature) Added "visibility" option to "tkwait" command to make
it easier to wait for a new window to appear on the screen.

---------------------- Release 3.1, 2/5/93 -------------------------

2/10/93 (installation improvements) Makefile improvements:  added RANLIB
variable for easier Sys-V installation, changed to use INCLUDE_DIR
properly, and added SHELL variable for SGI systems.

---------------------- Release 3.2, 2/11/93 -------------------------

2/11/93 (new feature) Added "wm state" command, and improved wm so that
the right thing will happen if you invoke "wm iconify" when a window is
withdrawn.

2/14/93 (bug fix) When -colormap option was used in generating Postscript
for canvases, Tk didn't add an extra space after the color command.

2/14/93 (new feature) Changed "extern" declarations in tk.h to "EXTERN",
which will use the definition of EXTERN from tcl.h and work correctly
in C++ programs.

2/18/93 (bug fix) Item-specific bindings weren't getting deleted from
canvas items when the items were deleted.  As a result, they could
suddenly re-appear for new items if the new items were allocated a
record at the same addresses as the old ones.

2/18/93 (feature reversal) Changed "after" back again, so that it sleeps
*without* responding to events when it is invoked with just one argument;
can always use tkwait plus after with additional arguments to achieve
the effect of responding to events.
*** POTENTIAL INCOMPATIBILITY ***

2/20/93 (bug fix) Fixed bug in tkWindow.c where colormaps weren't being
set correctly for new top-level windows on different screens than their
parents (the bug results in X protocol errors: "invalid Colormap
parameter").

2/22/93 (bug fix) Changed "#!/usr/local/wish" in demo scripts to
"#!/usr/local/bin/wish" to reflect new location of binary.

2/22/93 (new feature) Added new reliefs "groove" and "ridge".

2/25/93 (new feature) Added new built-in bitmaps:  "error", "hourglass",
"info", "question", "questhead", and "warning".  Also added new demo in
"widget" to display all of these (under the Miscellaneous menu).

2/25/93 (improved implementation) Changed DrawText procedure in
prolog for outputting Postscript from canvases to use stringwidth
instead of charpath+pathbbox:  avoids limitcheck problems with long
strings, and also properly includes space characters in calculation.

2/25/93 (bug fix) Fixed several bugs in library/menu.tcl that caused
menu traversal to mis-behave when menu had no entries.

2/26/93 (new feature) Added "wm frame" command.

3/6/93 (bug fix) Mwm in click-to-focus mode was goofing up grabs so that
pull-down menus were sometimes unresponsive.  Modified tk.tcl to ignore
the spurious B1-Enter events generated by mwm, plus modified tkGrab.c to
release simulated button grabs correctly.

3/8/93 (bug fix) Tk had wrong interpretation of "lbearing" font metric,
which caused text to be displayed at the wrong horizontal position in
several places (labels/buttons, listboxes, canvas text, scales).  This
change will cause slight changes in the way certain widgets are
displayed.

3/12/93 (bug fix) Fixed core dumps that occurred in tkEntry.c because of
zero values in entryPtr->avgWidth.

3/12/93 (bug fix) Tk_CoordsToWindow was using root coordinates always.
Changed to use virtual-root coordinates when a virtual-root window
manager is being used.  Before this fix, "winfo containing" didn't
return the correct window under virtual-root window managers.

3/18/93 (bug fix) Modified tkWm.c so that Tk doesn't fight with window
manager over position of window;  it just takes what the window manager
gives it.

3/21/93 (new feature) Changed menus to display cascade entries with
standard Motif arrows at right side.a

3/22/93 (bug fix) Fixed bug in tkPack.c that was causing memory to
get trashed with the integer value 1.

3/22/93 (bug fix) Canvas text didn't print correctly if it contained
an open paren (or other special character) immediately followed by
an octal digit.

3/22/93 (bug fix) Text widgets didn't redisplay properly in cases
where two or more groups of lines both got taller at the same time
(e.g. from tag changes), causing two separate bit copies where the
first bit copy's target area overlapped the source area for
the second bit copy.

4/1/93 (bug fix) Changed canvases to use ISO Latin-1 font encoding
if that's supported by the Postscript interpreter.  Also added workaround
for bug in NeWSprint related to stipple fills.

4/1/93 (bug fixes) Made various changes to focusing and grabs to
eliminate extraneous focus events and generally improve behavior.

4/2/93 (bug fix) Modified tkWm.c not to wait indefinitely for the window
manager to map or reconfigure a window:  this led to deadlock in some
situations, such as creating a new top-level window with a grab held.

4/19/93 (bug fix) Fixed another bug in tkWm.c that caused windows to walk
across the screen in some situations.  Also fixed problem where rapid
posting and unposting of cascaded submenus (or menus?) could cause Tk
to become confused about whether or not a window is mapped (added
TkWmUnmapWindow procedure to make top-level unmaps synchronous).

4/24/93 (feature change) Changed the "after" command to allow times
less than or equal to 0, and to use 0 whenever they occur.

4/26/93 (new feature) Implemented security check for "send" as proposed
by Bennett Todd: incoming sends are now rejected unless (a) xhost-style
access control is enabled and (b) the list of authorized hosts is
empty.  In other words, you have to use xauth to use send.  This feature
can be disabled by setting the TK_NO_SECURITY flag at compile-time.

5/15/93 (improvement) Switched to use Tcl_PrintDouble whenever returning
real values as Tcl results.  This potentially allows higher precision.
Switched to use %.15g whenever printing reals in Postscript files.
However, the change Tcl_PrintDouble causes incompatibilities.  For
now, it's disabled with a macro in tclInt.h that redefines Tcl_PrintDouble.
Tk 4.0 will delete the macro, and you can also delete it now if you
want the better (but incompatible) behavior.

5/19/93 (bug fix) Fixed divide-by-zero problem that could occur in
closeness calculations for canvas oval items.

5/30/93 (bug fix) PROP and CONFIG were accidentally #defined to the same
value in tkBind.c, which could cause incorrect %-substitutions in event
bindings in a few exotic cases.

6/4/93 (improvement) Changed to use GNU autoconfig for configuration.
Makefile format changed, and Tcl is no longer automatically included
in Tk releases.

6/7/93 (bug fix) Fixed off-by-one error in rounding negative coordinates
during redisplay of canvases.

6/9/93 (feature improvement) Modified default bindings for entries to
keep one character visible to the left of the cursor during backspaces.

6/18/93 (feature improvement) Added patchlevel.h, for use in coordinating
future patch releases, and also added tk_patchLevel variable to make the
patch level available in scripts.

6/26/93 (bug fix) Fixed numeric problems in scales that occurred with
very large scale values.

6/26/93 (bug fix) Polygon items in canvases could cause core dumps if
the "coords" widget command was used to add one new coordinate.

6/26/93 (bug fix) Changed canvases to handle large stipple patterns
gracefully (stipples used to jump around during redisplay and lose
coherency).

7/1/93 (syntax change, new feature) Implemented the new packer syntax
as described in the book.  For now the old syntax will continue to be
supported too.  Converting over is straightforward except (a) use
"-anchor" instead of "frame", and (b) padding is different (separate
internal and external padding, plus pad amounts are *on each side*
instead of total).  Also added "pack propagate" command for keeping
the packer from setting the master's requested size.

7/1/93 Changed copyright notices.  The effect is the same as with the
old notices, but the new notices more clearly disclaim liability.

7/7/93 (new feature) Added support for window stacking order.  Windows
will now stack in the order created (most recent on top), plus "raise"
and "lower" commands may be used to restack (Tk_RestackWindow procedure
is available from C level).

7/7/93 (reorganization) Moved main.c to tkMain.c, reorganized it to
call Tcl_AppInit just like tclsh does, and added argv0 variable to contain
application name, and added default Tcl_AppInit procedure for wish.
Also added tkTest.c to hold C code for testing.

7/7/93 (new feature) Added new Tk-specific "exit" command, which cleans
up properly before exiting.  It replaces the Tcl "exit" command, and
can be used in place of "destroy .".

7/9/93 (new features) Added tk_dialog library procedure that creates
dialogs with a bitmap, message, and any number of buttons.  Also changed
default tkerror procedure to use tk_dialog plus offer the user a chance
to see a Tcl stack trace.

-------------------- Release 3.3 Beta 1, 7/9/93 -------------------------

7/12/93 (configuration changes) Eliminated leading blank line in
configure script;  provided separate targets in Makefile for installing
binary and non-binary information; fixed -lnsl and -lsocket handling
in configure; added autoconf support for fd_set type; check for various
typedefs like mode_t and size_t, and provide substitutes if they
don't exist; don't include tkAppInit.o in libtk.a; try to locate the
X includes and library in all of the standard places for various systems.

7/14/93 (new feature) Modified tkMain.c so that it stores the value
of the -display command-line option into the DISPLAY environment
variable, if it is specified.

7/15/93 (feature removal) Removed auto-initialization feature from
Tk_ConfigureWidget, so that you must once again initialize all fields
of a widget record before calling Tk_ConfigureWidget.  This restores
the behavior back to what it was in Tk 3.2.

7/16/93 (bug fix) Modified tkBind.c to ignore the Caps Lock modifier
unless it is explicitly requested in a binding.  Without this fix,
buttons and menus and other things didn't work if the Caps Lock key
was active.

-------------------- Release 3.3 Beta 2, 7/21/93 -------------------------

7/21/93 (new feature) Change "make install" so that it will modify the
#! lines on demo scripts to reflect the place where the wish binary
is installed.

7/23/93 (new feature) Added Tk_MainWindow procedure that returns the
main window associated with a Tcl interpreter.  This is intended for
use by Tcl_AppInit and other initialization procedures.

7/24/93 (configuration improvements) Changed configure script not to
omplain about "fd_set" missing if it's defined in <sys/select.h>.

7/28/93 (bug fix) "Bad Match - parameter mismatch" errors were
sometimes occurring when several top-level windows got created
at the same time, due to wrong choice of sibling when stacking
windows.

8/14/93 (new feature) Added support for tcl_prompt1 and tcl_prompt2
to wish main program:  makes prompts user-settable.

8/19/93 (bug fix) Bindings to event sequences like "aD" never matched
because the Shift key has to be pressed before D.  Modified Tk to
ignore extraneous keypresses if they are for modifier keys.

8/26/93 (configuration changes) Added Tk_Init, modified Tcl_AppInit
procedures to use it and Tcl_Init.  Added support for .wishrc file.

8/28/93 (new feature) The main window is now a legitimate toplevel
widget.

-------------------- Release 3.3 Beta 3, 8/30/93 -------------------------

9/2/93 (bug fix) The packer wasn't always relaying out a master after
changes to some of the configuration options of its slaves.

9/2/93 (bug fix) The binding mechanism made it impossible for patterns
like <Double-ButtonRelease-1> to ever match.

9/2/93 (bug fix) Fixed core dump that occurred for bitmap canvas items
if Postscript is generated but no -bitmap option has been specified.

9/4/93 (enhancement) Slight improvements to menu traversal:  set menu
traversal bindings for menubar window in tk_menuBar, plus trigger
traversal on <Any-Alt-Keypress> instead of <Alt-Keypress>.

9/9/93 (bug fix) Changed tkBind.c so that the Num_Lock key doesn't
prevent events from triggering bindings.

9/9/93 (bug fix) Changed tkOption.c to always fetch RESOURCE_MANAGER
property from root window of screen 0, rather than using default
screen.

9/9/93 (bug fix) Entry widgets weren't allocating quite enough width
for themselves.  Fixed this and changed the size computation to match
what's done for buttons and texts.

9/16/93 (bug fix) Changed tkMain.c not to call exit C procedure directly;
instead always invoke "exit" Tcl command so that application can redefine
the command to do additional cleanup.

-------------------- Release 3.3, 9/29/93 -------------------------

9/30/93 (bug fix) Packer wasn't unmapping slaves when master got deleted.

9/30/93 (bug fix) Binding event sequences such as <Right> were being
misprinted as ASCII characters such as "S".

10/6/93 (bug fix) Canvases weren't unmapping window items when the canvas
got unmapped, which caused problems for window items whose windows weren't
descendants of the canvas (they got left on the screen).

10/7/93 (feature change) NULL proc arguments to Tk_CreateFileHandler used
to have a special undocumented meaning (fd was display);  eliminated this
special interpretation.

10/7/93 (configuration change) Eliminated dependency of tkMain.c on
tkInt.h and tkConfig.h, so that it's easier for people to copy the file
out of the source directory to make modified versions.

10/8/93 (bug fix) 3.0 introduced a bug where the class of the application
wasn't being set properly, so options based on the application class
weren't triggering.  Fixed by adding new argument to Tk_CreateMainWindow.

10/11/93 (bug fix) Fixed bug in tkTextBTree.c where some deletions would
cause core dumps due to halfwayLinePtr not getting set correctly.

10/18/93 (bug fix) Fixed a couple of bugs that made it hard to actually
display N characters in an entry with "-width N" (tended to scroll the
entry so that only N-1 characters were visible at once).

10/22/93 (bug fix) During configuration, XINCLUDE_DIR and XLIBRARY_DIR
weren't overriding xmkmf like they were supposed to.

10/23/93 (new feature) Allow negative scale factors in canvas "scale"
widget command.

10/23/93 (bug fix) Grabs weren't being cleaned up right if the grab
window was deleted, causing core-dumps in some cases.

10/23/93 (bug fix) tk_TextSelectTo wasn't checking to be sure that
the "anchor" mark exists.

10/27/93 (bug fix) Fixed core dump that could occur in a text widget if
the scroll command modifies the text.

11/1/93 (bug fix) Change texts so that the -yscrollcommand option is
invoked at display time, not when the window is re-layed out.  This
eliminated various core dumps that could occur if -yscrollcommand modified
the text.

-------------------- Release 3.4, 11/04/93 -------------------------

Note: there is no 3.5 release.  It was flawed and was thus withdrawn
shortly after it was released.

11/12/93 (bug fix) TkMain.c didn't compile on some systems because of
R_OK in call to "access".  Changed to eliminate call to "access".

-------------------- Release 3.6, 11/26/93 -------------------------

11/10/93 (bug fix) Packer and placer didn't always reposition a window
correctly if it was managed inside a neice or lower descendant (using
"-in" option) and the neice's parent moved.

11/24/93 (bug fix) Fixed time problem in selection (retrievals could
fail if retriever hasn't received any X events since selection was
made, so that time of retrieval appears to be older than time of
selection).  Selection code is now much less picky about times, both
on retrieving and supplying sides.

12/2/93 (new feature) Changed arrow-head drawing code for canvas
lines to draw a 0-width outline in addition to filling the area:
this produces much nicer, more symmetrical displays.

12/2/93 (bug fix) When colors ran out, Tk was invoking "tkerror"
when its state was internally inconsistent, which could cause
core dumps in some situations (e.g. if tkerror used the same color
that caused colors to run out).  Changed notification to occur
as a when-idle handler.

12/3/93 (bug fix) During a global grab, Tk wasn't including PointerMotion
in the list of grabbed events, so pointer motion couldn't be tracked
outside the grabbing application.

12/3/93 (bug fix) Canvases didn't handle smoothed lines correctly
when they only contained two points.

12/3/93 (bug fix) Fixed bug in tkWindow.c where certain kinds of
errors during window creation could cause Destroy events to be generated
for a window that was never completely initialized.

12/13/93 (bug fix) Fixed bug in tkTextDisp.c that resulted in core
dumps at line 1467 under exmh.  The exact situation is that a text
widget was being redisplayed at a time when it had a -yscrollcommand
option but hadn't yet been mapped onto the screen.

12/17/93 (bug fix) Fixed bug in tkWindow.c whereby new top-level windows
with non-default visuals still inherited border pixmap from parent (root),
which could cause visual clash and X error.

12/17/93 (bug fix) Fixed bug in tkTextDisp.c that caused round-off
error in the information passed to scroll commands.

12/18/93 (bug fix) Fixed bug in tkPack.c that caused core dumps in
some situations if a master with siblings packed "-in" it was deleted.

12/18/93 (bug fix) Added "compat" directory to distribution, since it's
referenced by tkConfig.h on some systems.

12/18/93 (performance improvement) Improved performance of appending to
a listbox, so that inserting N items doesn't take N**2 time.

12/20/93 (bug fix) Fixed bug in canvas ovals that caused the fill color
for the oval to stick out past the outline.

1/2/94 (fixed Xlib bug) Added code to reuse X resource identifiers so
that they won't run out in long running applications.  There are three
new library procedures: Tk_FreeXId, Tk_GetPixmap, and Tk_FreePixmap.
Modified all Tk code to use these procedures, so wish applications should
now be able to run forever without running out of identifiers.

1/10/94 (bug fix) tkCursor wasn't freeing pixmaps used to create
cursors, which caused memory leaks in programs that changed cursors
frequently.

1/21/94 (bug fix) Fixed bug in scales that caused them to loop
infinitely drawing tick-marks when -from and -to were the same.

2/2/94 (bug fix) Fixed problem where messages that contained tabs
didn't always compute the correct size, so that text spilled off
the right edge.  The fix adds an extra "tabOrigin" parameter to
the internal procedures TkMeasureChars, TkDisplayChars, and
TkUnderlineChars.

2/4/94 (bug fix) Fixed off-by-one problem in tkBind.c that caused
it to read past the initialized part of dispPtr->modKeyCodes.

2/7/94 (bug fix) Text widgets didn't handle grabs correctly, such
that the "current" character got stuck if a grab occurred while a
mouse button was down.  It would get unstuck until after the
next button press and release.

2/19/94 (bug fix) Fixed prolog.ps (prolog for Postscript printing from
canvases) so that it correctly prints all of the characters in the
ISO Latin-1 character set.

2/19/94 (bug fix) Modified tkBind.c to save and restore the interpreter's
result across the execution of binding scripts.  Otherwise if an event
triggers in the middle of some other script (e.g. a destroy event during
window creation, because there was an error in the creation command),
the intepreter's result gets lost.

2/19/94 (bug fix) Fixed bug in dealing with results of sent command
that could cause them to get lost in some situations.

2/21/94 (bug fix) Don't let user close a dialog window created by
tk_dialog, since this would cause tk_dialog to hang:  force the user
to select one of the dialog's buttons.

2/21/94 (bug fix) Fixed bug in canvas polygons whereby they didn't
correctly handle changes in the number of points (via "coords"
widget command).

2/23/94 (bug fix) Large bitmaps in canvases didn't print correctly
because they overflowed the 64-KB limit on strings in Postscript.
Changed canvas printing to split up large bitmaps into mutliple
smaller ones for printing.

2/25/94 (bug fix) The "." window was being set up with -width
and -height options, which interfered with geometry management (any
configuration change on "." causes the window to change size to
200x200, then change back again).

2/26/94 (bug fix) Fixed several bugs that occurred when a Destroy
event handler for a window deleted the window's parent.

3/3/94 (new features) Changes to binding mechanism:
    - The modifiers for "Alt", "Meta", and "M" are now computed by
      examining the modifier map, rather than being hardwired to
      M2, M1, and M1.
    - When processing events, one script is invoked for each object
      in the list passed to Tk_BindEvent, rather than stopping as
      soon as a script is invoked for some object.  The "break" and
      "continue" commands can be used within a script to abort all
      scripts for the event or the current one.
      *** POTENTIAL INCOMPATIBILITY ***
    - Added "bindtags" command so that new binding groups can be
      defined for widgets and the evaluation order can be changed.
    - When matching events to bindings, extra modifiers are now ignored,
      as if "Any" were specified for every event.  The "Any" modifier
      is still recognized, but it is ignored and is deprecated.
      *** POTENTIAL INCOMPATIBILITY ***
    - In % sequences that print window identifiers (e.g. %a and %S), print
      in hexadecimal rather than decimal, for consistence with "winfo id".
      *** POTENTIAL INCOMPATIBILITY ***
    - The "bind" command no longer supports the event types CirculateRequest,
      ConfigureRequest, MapRequest, or ResizeRequest.  These event types
      are somewhat dangerous, and they never worked anyway.

3/13/94 (bug fix) Fixed numerous problems with the "wm iconwindow" command.
It appears that this command never really worked at all, but it should
work OK now.

3/14/94 (feature changes) Removed several obsolete features:
    - Eliminated "enable" and "disable" widget commands for menus.
      *** POTENTIAL INCOMPATIBILITY ***
    - Eliminated "activate" and "deactivate" widget commands for buttons,
      checkbuttons, radiobuttons, and menubuttons.
      *** POTENTIAL INCOMPATIBILITY ***
    - Removed -geometry option for frames and toplevels:  it causes
      problems when .Xdefaults files contain entries like
      "*geometry: +0+0".  Must use -width and -height instead.
      *** POTENTIAL INCOMPATIBILITY ***
    - Desupported "tkVersion" variable: use "tk_version" instead.
      *** POTENTIAL INCOMPATIBILITY ***

3/16/94 (feature changes) Changes to listboxes:
    - Eliminated -geometry option (it causes problems when .Xdefaults
      files contain entries like "*geometry: +0+0").  Added -width
      and -height options to use instead.
      *** POTENTIAL INCOMPATIBILITY ***

3/21/94 (bug fix) Fixed bug in tkOption.c where the option cache wasn't
properly cleaned up after window deletion;  this could cause the wrong
value from the option database to be used under some conditions.

3/25/94 (new features) Changes to geometry management:
    - Added Tk_MaintainGeometry and Tk_UnmaintainGeometry procedures
      to solve problems with -in windows.  Modified the packer, the
      placer, and canvases to use them.
    - Changed 2nd argument to Tk_ManageGeometry from Tk_GeometryProc *
      to a pointer to a structure with additional information about
      the geometry manager, such as name and procedure to call when
      slaves are stolen.
      *** POTENTIAL INCOMPATIBILITY ***

3/28/94 (new feature) Overhauled event management:
    - Added "cancel" option to the "after" command so that you can
      cancel previously-scheduled commands.
    - Separated X-specific stuff from generic event management.  The
      file tkEvent.c can now be used stand-alone without the rest of Tk.
      See the manual entry for Tk_EventInit for information on which
      procedures are available this way.
    - Added Tk_CreateFileHandler2 procedure, which provides a lower-level
      and more powerful form of file event handler.
    - Fixed bug in Tk_DoOneEvent where an infinite loop could occur if
      the TK_FILE_EVENT and TK_DONT_WAIT flags were set simultaneously
      (there were bugs with several other combinations too;  all should
      be fixed now).

3/28/94 (new feature) Added "fileevent" command, which allows event-
driven I/O in the style of Mark Diekhans' "addinput" command.

4/11/94 (new feature) Better support for colormaps and visuals:
    - Added new -colormap and -visual options to toplevels and frames.
    - Added "winfo visualsavailable" command.
    - Added "wm colormapwindows" command, plus support for WM_COLORMAP_WINDOWS
      to Tk_SetWindowColormap.
    - Added new library procedures Tk_GetVisual, Tk_GetColormap,
      and Tk_FreeColormap.

4/11/94 (bug fix) Fixed core dump that used to occur when specifying
an iconwindow ("wm iconwindow") for a toplevel on a different screen
than the main window.

4/23/94 (new feature) Added support for images, including the following:
    - New "image" command for creating images.
    - Built-in image type: bitmap.
    - New "image" item type in canvases.
    - Labels, buttons, checkbuttons, radiobuttons, menubuttons, and
      menu entries now support a -image option for displaying images.
    - Tk_CreateImageType and Tk_ImageChanged procedures, for defining
      new types of images in C.
    - Tk_GetImage, Tk_FreeImage, Tk_RedrawImage, and Tk_SizeOfImage
      procedures, for using images in widgets.

5/1/94 (new features) Added new procedures Tk_3DVerticalBevel and
Tk_3DHorizontalBevel.

5/11/94 (new features) Major overhaul of text widgets:
    - Implemented embedded windows and "window" widget command.
    - Added new configuration options for tags: -justify, -lmargin1,
      -lmargin2, -rmargin, -offset, -spacing1, -spacing2, and -spacing3.
      See the "Display styles" widget demo for examples.
    - Added new configuration options for texts: -spacing1, -spacing2,
      and -spacing3.
    - Added "tagList" option to "insert" widget command to control
      tags on new text.  Made tagged regions so they aren't sticky on
      either side:  new characters get a tag only if the old chars. on
      both sides had it.
      *** POTENTIAL INCOMPATIBILITY ***
    - Added gravity for marks, and "mark gravity" widget command.
    - Added horizontal scrolling, "xview" widget command, -xscrollcommand
      option.  Changed "scan" widget commands to support horizontal
      scrolling.
      *** POTENTIAL INCOMPATIBILITY ***
    - Added "search" widget command for searching (either exact matches
      or regular expressions).
    - New widget commands: bbox, dlineinfo, and see.
    - Changed implementation of bindings so that Enter and Leave
      events are not generated unless the tag has just become present
      (or just ceased to be present) on the current character.  Also
      changed bindings to process separately for each tag, rather than
      having high-priority tags override low-priority ones.
    - The "end" index now refers to the character after the last newline
      rather than the newline itself.  You can now tag the final newline
      and set a mark after the final newline.
    - Deletions of the "sel" tag and the "insert" and "current" marks
      are now ignored silently, rather than generating errors.  This means
      you can do things like "eval .t tag delete [.t tag names]".

5/19/94 (bug fix) Canvases didn't generate proper Postscript for stippled
text.

5/20/94 (new feature) Added "bell" command to ring the display's bell.

5/20/94 (new feature) Incorporated "square" demonstration widget into
tktest application.

5/20/94 (new features) Changed wish application (tkMain.c):
    - wish no longer processes the -help option.
      *** POTENTIAL INCOMPATIBILITY ***
    - The wish main program is now called Tk_Main;  tkAppInit.c has a
      "main" procedure that calls Tk_Main.  This makes it easier to use
      Tk with C++ programs, which need their own main programs, and it
      also allows an application to prefilter the argument list before
      calling Tk_Main.
      *** POTENTIAL INCOMPATIBILITY ***
    - The application's class is now the same as its name (except the
      first letter is capitalized), instead of "Tk".
      *** POTENTIAL INCOMPATIBILITY ***
    - The -file keyword is no longer required:  the script file name can
      be provided as the first argument without being preceded by "-file",
      as in tclsh.  For backward compatibility the "-file" keyword is
      ignored if it is the first argument, but it is deprecated.

5/26/94 (feature removed) Removed support for "fill" justify mode from
Tk_GetJustify and from the TK_CONFIG_JUSTIFY configuration option.  None
of the built-in widgets ever supported this mode anyway.
*** POTENTIAL INCOMPATIBILITY ***

5/27/94 (feature change) Changed Tk to use Tk_PrintDouble everywhere
that it converts reals to strings.  This means that floating-point
values will be generated in some cases where integer-like values were
generated before.
*** POTENTIAL INCOMPATIBILITY ***

6/1/94 (feature change) Renamed "pack newinfo" command to "pack info".
The old "pack info" command is no longer available.
*** POTENTIAL INCOMPATIBILITY ***

6/20/94 (feature changes) Overhaul of entry widgets:
    - Added "-justify" option.
    - Added "-show" option to make entries easier to use for passwords.
    - Added "cget" widget command.
    - Added "selection range" and "selection present" widget commands.
    - Added "anchor" symbolic index.
    - Changed "-scrollcommand" option to "-xscrollcommand", "view"
      widget command to "xview", for compatibility with other widgets.
      *** POTENTIAL INCOMPATIBILITY ***
    - Changed sel.last to refer to character just *after* last one
      selected, again for compatibility with other widgets.
      *** POTENTIAL INCOMPATIBILITY ***
    - For "delete" widget command, second index now refers to character
      just *after* last one to delete.
      *** POTENTIAL INCOMPATIBILITY ***
    - Overhauled bindings to be more Motif-compatible and to include
      common Emacs bindings for editing.
    - Changed -width option:  if specified as 0, widget sizes to fit
      its current text.

6/11/94 (new features) Improved Motif compatibility:
    - Added "-highlightwidth" and "-highlightcolor" options to all widgets.

6/27/94 (bug fix) Postscript generation for text items in canvases was
not justifying the text properly when a -width was specified that was
longer than the longest line.

6/27/94 (bug fix) "winfo exists" used to report a window as existing
if it was in the process of being destroyed (i.e., a destroy handler
is in the middle of execution).  Changed to report it as non-existent
under these conditions.
*** POTENTIAL INCOMPATIBILITY ***

7/11/94 (bug fix) Selections claimed via "selection own" weren't always
being cleared properly when the selection was claimed away.  Also fixed
bug where Tk wasn't properly claiming the selection, if there haven't
been any recent X events at the time of the claim.

7/13/94 (feature changes) Overhaul of scrollbar widgets:
    - New widget commands: "activate", "cget", "fraction", and "identify".
    - New options: -activebackground, -activerelief, -highlightcolor,
      -jump, -highlightthickness, and -troughcolor.  What used to be
      -background is now -troughcolor, -foreground is now -background,
      and -activeforeground is now -activebackground.
      *** POTENTIAL INCOMPATIBILITY ***
    - Added new syntax for "set" command, "get" result, and generated
      commands.  Changed other widgets to use the new syntax.
    - Moved the bindings out of C and into Tcl scripts, using the new
      options and widget commands.  Added support for all Motif
      bindings, plus jump scrolling and cancelling of slider drags.

7/16/94 (bug fix) Canvases assumed that the Leave event for one item
didn't modify or delete the next current item;  this could cause core
dumps under some conditions.

7/23/94 (feature change) Modified Tk_BackgroundError so that tkerror
is invoked as an idle handler.  If tkerror generates a break exception
then all other queued reports are aborted.

8/14/94 (bug fix) "cursorOffTime" and "cursorOnTime" were confused in
canvases, resulting in the same time being used for both.

8/16/94 (bug fix) "tkwait variable" command didn't detect errors in
variable name, such as trying to wait for an entire array.

9/2/94 (new features) Overhaul of scale widgets:
    - Floating-point values are supported now, following Paul Mackerras'
      "fscale" widget.  Added "-resolution" and "-digits" options.
    - Added "-variable" option to link scale to variable, following
      Henning Schulzrinne's implementation.
    - Added focus highlight (-highlightthickness and -highlightcolor
      options).
    - Added new widget commands "cget",  "coords", "identify", plus
      improved "get";  removed wired-in bindings, added complete set
      of Motif bindings via Tcl scripts.
    - Changed -sliderforeground option to -background, -background to
      -troughColor, -activeforeground to -activebackground.
      *** POTENTIAL INCOMPATIBILITY ***
    - Moved value label from below horizontal scales to above the scale,
      for Motif compliance.

9/9/94 (bug fix) Fixed bug in tkWm.c that caused long delays in "raise"
command under some conditions (window already at the top of the stack).

9/10/94 (new features) Overhaul of label/button/checkbutton/radiobutton
widgets:
    - Added focus highlight (-highlightthickness and -highlightcolor
      options).
    - Added new widget command "cget".
    - Changed -selector option to -selectcolor, and changed its meaning
      too: empty no longer means don't draw the indicator;  it means
      don't use a special color when selected.
      *** POTENTIAL INCOMPATIBILITY ***
    - Added -indicatoron (controls whether indicator is displayed) and
      -selectimage (gives special image to display when selected) options.
    - Modified bindings to be more Motif-like, added binding for space
      key.
    - Changed padding defaults to give widgets correct Motif appearance
      by default.  Also, changed to ignore padding options when displaying
      an image or bitmap.
      *** POTENTIAL INCOMPATIBILITY ***
    - Can now display text on multiple lines:  newlines cause line breaks,
      and word wrapping can be requested with -wraplength option.  Also
      added -justify and -underline options.
    - The -value option for radiobuttons can now have an empty string as
      its value;  it no longer defaults to the name of the widget.
      *** POTENTIAL INCOMPATIBILITY ***

9/13/94 (new features) Modified both canvases and messages to support
-highlightthickness and -highlightcolor options plus "cget" widget
command.

9/19/94 (new features) Added Tk_UnsetGrid procedure, modified widgets
to use it.  Also changed Tk_SetGrid so that at most one window per
toplevel can have gridding enabled.

9/23/94 (new features) Major overhaul of listbox widgets:
    - Added focus highlight (-highlightthickness and -highlightcolor
      options).
    - Added new widget command "cget".
    - Revised selection commands to support single selections as well
      as multiple disjoint selections;  syntax of "selection" widget
      command has changed to support this.  Added new option -selectmode
      for specifying which mode to use.  Default is single selection;
      tk_listboxSingleSelect procedure no longer exists.  Selections
      now return as items separated by newlines instead of a list whose
      elements are the items.
      *** POTENTIAL INCOMPATIBILITY ***
    - Extended "get" widget command to allow many items to be retrieved
      at once.
    - Added "bbox" widget command for finding position of an element on
      screen.
    - Added "activate" command to mark element with traversal focus.
    - Extended index mechanism to support new types of indices:
      "active", "anchor", "@x,y".
    - Added "see" widget command.
    - Revised bindings to include all Motif features except for AddMode.
    - If -width or -height option is <= 0, the widget requests a size just
      large enough to hold all of its text.

10/6/94 (new features) Overhaul of menubuttons:
    - Added focus highlight (-highlightthickness and -highlightcolor
      options).
    - Added new widget command "cget".
    - Added -indicatoron option to display option menu indicator.
    - The -menu option must be a child of the menubutton.
      *** POTENTIAL INCOMPATIBILITY ***

10/6/94 (new features) Overhaul of menu widgets:
    - Added new widget commands "cget" and "entrycget".
    - Changed the implementation of tear-off menus to be more
      Motif-like;  added -tearoff option for specifying whether
      tearoff entry is displayed.
    - Changed interpretation of "@y" index:  it now returns the
      closest entry, rather than "none" if y is outside the menu's
      range.
      *** POTENTIAL INCOMPATIBILITY ***
    - The -menu option for a cascade entry must now be a child of
      the menu.
      *** POTENTIAL INCOMPATIBILITY ***
    - Added "type" widget command, so that you can query the type of
      an entry.
    - Added -foreground, -activeforeground, -selectcolor, -indicatoron,
      -image, and -selectimage options to menu entries.
    - Changed "selector" menu option to "selectColor" for Motif compliance.
      *** POTENTIAL INCOMPATIBILITY ***
    - Added -relief option for menus, just for consistency with other
      widgets (it was implicitly "raised" before).

10/6/94 (feature change) Completely overhauled the bindings for menus
and menubuttons.  They now fit better with other Tk 4.0 facilities,
such as the new binding mechanism, and they provide better Motif
compliance (e.g. keyboard traversal of submenus).  Also, the bindings
now support option menus, popup menus, and proper Motif tear-off
menus.

10/6/94 (obsolete features) The procedures tk_menuBar and
tk_bindForTraversal are no longer needed in Tk 4.0.  They still exist
for compability, but they do nothing.

10/6/94 (new procedures) Added "tk_popup" procedure for posting a
popup menu, and "tk_optionMenu" for creating an option menubutton
and its associated menu.

10/6/94 (change in name) The variable "tk_priv" has been renamed
to "tkPriv" to reflect that fact that it is private to Tk now.
This shouldn't cause any problems, since no-one except Tk should
have been using it before anyway (right?).

10/6/94 (bug fix) Fixed bug in texts where sometimes the text would
stop tracking mouse motion (the "current" item wouldn't get updated)
because the text widget missed a ButtonRelease event.

10/20/94 (new features) Overhauled selection code to support multiple
selections (primary, secondary, etc.) and multiple displays:
    - Changed "selection" command to support new options such as
      "-displayof" and "-selection".  Old command formats are still
      supported for compatibility, but they are no longer documented
      and are deprecated.
    - Changed procedures Tk_GetSelection, Tk_CreateSelHandler, and
      Tk_ClearSelection to take additional "selection" argument.
      *** POTENTIAL INCOMPATIBILITY ***
    - Selection targets APPLICATION and WINDOW_NAME have been replaced
      by TK_APPLICATION and TK_WINDOW.
      *** POTENTIAL INCOMPATIBILITY ***

10/20/94 (new features) Added support for clipboard:
    - New "clipboard" command.
    - C procedures Tk_ClipboardClear and Tk_ClipboardAppend.
    - Bindings for "cut", "paste", and "copy" for text and entry widgets,
      plus "copy" binding for listboxes.

10/24/94 (bug fix) Button widgets weren't checking for errors when
setting the values of associated variables.

11/3/94 (bug fix) Fixed bug whereby Tk would hang if "exit" was invoked
from inside a <Destroy> binding.

11/15/94 (new features) Overhaul of focus mechanism:
    - Added support for multiple displays:  separate focus windows are
      kept for each display.
    - Added support for keyboard traversal.
    - Changed focus model so Tk keeps track of a focus window for each
      top-level window and automatically sets the focus on Enter to the
      top-level.  Tk no longer synthesizes FocusIn and FocusOut events,
      but just uses the standard X mechanisms.  There is no "default"
      focus window anymore; the focus reverts to top-levels by default.
      *** POTENTIAL INCOMPATIBILITY ***
    - Changed focus command:  eliminated "focus default" and "focus none",
      added "-displayof" and "-lastfor" options.  An empty string is now
      used to signify "no focus" instead of "none".
      *** POTENTIAL INCOMPATIBILITY ***
    - Added library procedures tk_focusNext, tk_focusPrev, and
      tk_focusFollowsMouse.
    - Removed obsolete Tk_CreateFocusHandler:  must use FocusIn and
      FocusOut events now.
      *** POTENTIAL INCOMPATIBILITY ***

11/23/94 (new features) Overhaul of "send" command:
    - Added support for multiple displays: -displayof option to "send".
    - Added asynchronous sends: -async option to "send".
    - Eliminated fixed timeouts on sends:  as long as the target
      application appears to exist, the send will wait for it.
    - Stale entries get removed from the application registry now,
      so "winfo interps" should never return non-existent applications.
    - Can change the name of an application with "tk appname" command.
      This is also the preferred way of querying the application name
      now.
    - The errorCode and errorInfo variables are now propagated back to
      the sender now, so a full stack trace is available.
    - Tk checks display security on each send now, instead of just during
      initialization, so changes in the security status are seen immediately
      by all applications.
    - The above changes required changes to the data formats used for
      communication between source and target applications, so Tk 4.0
      applications cannot send to, or be sent from, Tk 3.6 applications.
      *** POTENTIAL INCOMPATIBILITY ***
    - The procedure Tk_RegisterInterp has been replaced with Tk_SetAppName.
      *** POTENTIAL INCOMPATIBILITY ***

12/6/94 (cleanup) Eliminated "interp" argument to Tk_GetColorByValue,
since it is no longer needed.
*** POTENTIAL INCOMPATIBILITY ***

12/7/94 (feature change) Changed the "wm" command so that top-level
windows are now resizable by default.  You can no longer specify
empty arguments to "wm maxsize" and "wm minsize".
*** POTENTIAL INCOMPATIBILITY ***

12/8/94 (new feature) Added new "photo" image type using code provided
by Paul Mackerras:  currently supports only PPM "P6" format images.

12/14/94 (new features) Canvas modifications:
    - Modified the interfaces between generic canvas code and the item
      types so that it's easy for people to write new item types outside
      of Tk.
    - Added support for transparent bitmap items:  just specify an
      empty string as the background color.
    - Changed the "xview" and "yview" commands for canvases to use the
      new scrolling syntax.
    - Eliminated -scrollincrement option.
      *** POTENTIAL INCOMPATIBILITY ***

12/14/94 (bug fix) Fixed bug where the dimensions of canvas arrowheads
scaled during a "scale" widget command, but the scaling was only
temporary and got lost on the next re-configure of the item.  The
correct behavior is for the arrowheads not to scale.

-------------------- Release 4.0b1, 12/23/94 -------------------------

12/26/94 (bug fix) Removed obsolete demos from Makefile (color, dialog,
size), fixed "install" target.

1/3/95 (bug fix) Fixed all procedure calls to explicitly cast arguments:
implicit conversions from prototypes don't work when compiling under
non-ANSI compilers.  Tk is now clean under gcc -Wconversion.

1/4/95 (bug fix) Used "screenX" without ever setting it in DisplayText
in tkCanvText.c:  caused tabs in canvas text items to get messed up.

1/4/95 (bug fix) Canvases forgot to register the built-in types if
Tk_CreateItemType was called before a canvas widget was created.

1/4/95 (bug fixes) Fixed glitches in various text bindings:
    - Up used to do nothing if the cursor was at 2.0.
    - Right used to make the cursor invisible if it was just before
      the final newline of the text.
    - Control-t didn't conform to Emacs;  made it conform to GNU Emacs.
    - Deleted Control-x binding, since it doesn't conform to anything and
      is confusing for Emacs users.

1/4/95 (bug fixes) Changed Control-t for entries just as for texts (see
above) an deleted Control-x for entries (see above).

1/4/95 (bug fix) The packer didn't map slaves unless the master was mapped;
this could cause slaves to get "lost" so that they weren't mapped until the
master resized.

1/5/95 (bug fix) Scrollbars weren't executing the proper code the first time
the mouse entered the widget;  this caused problems if tk_strictMotif was
set.

1/6/95 (bug fix) Fixed label/button/checkbutton/radiobutton/menubutton
widgets to allow arbitrary screen distances when specifying -width and
-height for an image or bitmap (the manual pages already documented this
but the code didn't implement it).

1/6/95 (new feature) Added very primitive support for input methods,
as suggested by Martin Forssen.  This should be enough for European
character sets (Compose key) but it isn't near enough for Asian
character sets.

1/8/95 (bug fix) Fixed problem in canvas "xview" and "yview" commands
where divide-by-zero errors could sometimes occur.

1/8/95 (bug fix) New event handler didn't properly handle files for
which both TK_READABLE and TK_WRITABLE were specified.

1/11/95 (bug fix) Fixed bug with text selections:  was returning count
too high for data, causing bogus garbage to appear when selection was
copied.

-------------------- Release 4.0b2, 1/12/95 -------------------------

1/27/95 (feature removal) Removed %D substitution from binding scripts:
wasn't portable, shouldn't be used anyway.
*** POTENTIAL INCOMPATIBILITY ***

1/27/95 (new features) Added -displayof options to the commands
"winfo atom", "winfo atomname", "winfo containing", "winfo interps",
and "winfo pathname".

1/27/95 (new feature) Added "idle" option to "after" command to run
scripts as idle handlers.

1/28/95 (new feature) Modified placer to make -x and -relx additive
if you specify both.  Same for -y and -rely, -width and -relwidth,
and -height and -relheight.  This makes it easy to make request such
as "make .a 2 pixels larger than .b".
*** POTENTIAL INCOMPATIBILITY ***

1/28/95 (new feature) Improved auto-grab mechanism in canvases (which
prevents current item from changing while a button is down):  changed
to report Enter and Leave events for the current item while a button
is down.  However, as before, no Enter events are reported for other
items until the button goes up.

1/28/95 (new feature) Bitmap images are now transparent if the -background
is specified as an empty string (-maskdata and -maskfile are ignored in
this case).  This is also the default.

1/28/95 (bug fix) Tk didn't support manufacturer- or site-specific keysyms
such as SunAudioMute.  Modified tkBind.c so that it uses XStringToKeysym
in addition to its own hash table, so that all keysyms are now available.

1/30/95 (feature change) Modified "clipboard append" so that it reclaims
the clipboard selection if it had been previously lost, rather than just
generating an error.  This handles certain race conditions more cleanly,
and also allows the use of programs like "xclipboard".

1/30/95 (new feature) Added -xscrollincrement and -yscrollincrement
options to canvases.

1/31/95 (bug fix) Geometry management was broken if a particular geometry
manager claimed a slave away from itself.

1/31/95 (bug fix) Fixed bug in tkVisual.c where a visual with fewer bits
than requested was being selected in preference to one with just the right
number of bits.

1/31/95 (bug fix) Texts weren't redisplaying the padding region properly
after changes in -padx or -pady.

1/31/95 (new features) More text improvements:
    - Extended "insert" widget command for texts to allow multiple
      text-tagList pairs in the same command.
    - Added -nocase option to "search" widget command.
    - Added -overstrike option to tags.
    - Added tab stops, via -tabs option for widget and for tags.

2/10/95 (bug fix) Modified all widgets to allow renaming of widget
commands.  Deleting a widget command will delete the widget.

2/11/95 (new feature) Added -highlightbackground option to all widgets.

2/14/95 (new feature) Added "insert" widget command for menus.

2/15/95 (new feature) Modified text display code (for all widgets) to
display well-known control characters like newline and backspace as
\n or \b instead of \xa.

2/15/95 (bug fix) Modified bitmap and photo image managers to delete
the image command when the image is deleted.  Also modified them to
allow renaming of the image command, and to delete the image if the
image command is deleted.

2/15/95 (bug fix) Fixed text widgets to allow horizontal scrolling
even if wrapping was enabled, if a line isn't entirely visible due to
a large character or embedded window.

2/16/95 (feature change) Added "postcascade" widget command to menus,
changed "invoke" and "activate" not to post or unpost submenus.  Also
fixed bug in redisplay that tended to leave bits of garbage on menu
when submenu unposted.
*** POTENTIAL INCOMPATIBILITY ***

2/16/95 (feature removal) Removed "snap back" behavior (slider
snaps back to old position if you move the mouse outside the widet
before releasing the button) from scrollbars and scales.

2/16/95 (bug fix) The last line of a listbox wasn't being displayed if
it was only partially visible.

2/16/95 (new features) Added support for "-resolution 0" (no rounding
of values) to scale widgets, plus smarter computation of how many digits
to display.

2/17/95 (bug fix) Fixed bug in text bindings for things like Shift-Left:
didn't properly set the anchor position.

2/20/95 (bug fix) Changed management of COLORMAP_WINDOWS property to
add the toplevel implicitly to the end of the list if it wasn't already
on the list somewhere.  Without this, some window managers implicitly
put it at the front of the list, so that colormaps in internal windows
are never used.

2/20/95 (bug fix) Changed to use separate command procedures for
button, checkbutton, label, and radiobutton commands.  This allows the
class commands to be renamed without breaking their behavior.

2/20/95 (removed feature) The "bind" command no longer supports
"Keymap" events;  they never worked anyway.

2/20/95 (bug fix) The text "search" widget command looped infinitely
when searching an empty text.

2/20/95 (bug fix) Canvases weren't redrawing their borders after
configuration changes.

2/20/95 (upgrade) Changed to use autoconf version 2.2.

2/21/95 (bug fix) Fixed several bug fixes in menu bindings that occur
when menus have no entries.

2/21/95 (bug fix) Fixed bug in geometry management that caused windows
packed -in siblings to not always be mapped and unmapped properly
(particularly when the toplevel got unmapped and mapped).

2/22/95 (bug fix) Fixed resource leak problem in tkTextDisp.c that
caused embedded windows not to be unmapped when off-screen.

2/23/95 (bug fix) "After cancel" dumped core when the script for an
after event cancelled itself.

2/24/95 (bug fix) Text and entry widgets weren't properly ignoring
Alt-, Control-, and Meta- keystrokes, so a widget-specific binding
for one of these resulted in the character also being inserted.

2/24/95 (bug fix) Several widgets accidentally performed unsigned
division on negative numbers, thereby losing the sign bit.  This
mostly affected the display of images and bitmaps in buttons,
menubuttons, and messages.

2/24/95 (feature reversal) Restored old behavior of %A so that it
returns non-printing characters as well as printing ones now.
*** POTENTIAL INCOMPATIBILITY with Tk 4.0b2, but not with Tk 3.6 ***

2/24/95 (bug fix) Duplicate "leave" events could occur for canvas
items under some conditions, due to recursive calls to PickCurrentItem.
Added code to detect and skip the nested calls.

2/24/95 (bug fix) Fixed bug where an error could occur during the first
keystroke in an application if its binding invoked "break".

2/25/95 (new feature) Modified syntax of "search" widget command for
texts.  The -nowrap switch and the "variable" final argument are no
longer supported.  Instead, there is a -count switch to replace
the final argument;  if the final argument is specified, it is now
a stopping index for the search.  The features of -nowrap can be
achieved now with the stopping index.
*** POTENTIAL INCOMPATIBILITY with Tk 4.0b2, but not with Tk 3.6 ***

2/27/95 (bug fix) Fixed problem that appears to prevent keyboard
input for working under IRIX:  tkBind.c was ignoring XmbLookupString
calls that returned a status of XLookupBoth.

2/27/95 (new feature) Added Tk_GetItemTypes procedure to return
information about available canvas item types.

2/27/95 (feature change) Changed Makefile to always use install-sh
for installations:  there's just too much variation among "install"
system programs, which makes installation flakey.

2/27/95 (bug fix) Fixed bug in tkSend.c that caused core dumps if
the app's main window was destroyed by a destroy handler on a
child.

3/5/95 (feature change) Change separator character used in "bind +..."
bindings from semi-colon to newline (permits bindings that are
comments, for what that's worth).

3/7/95 (bug fix/feature change) Overhauled focus code, both in C
and in Tcl:
    - Tk won't move the X focus in response to the "focus" command
      unless either the application already has the focus or the
      -force switch is specified.
    - Tk no longer sets the X focus to anything other than top-levels;
      it synthesizes events for FocusIn and FocusOut to children.
    - A window no longer has to be viewable when focussed to;  Tk will
      set the X focus later, when the window becomes viewable.
    - Added -takefocus option to all widgets.
    - Rewrote tk_focusPrev and tk_focusNext to use the -takefocus option.
      These procedures no longer set the focus;  they just return the
      next window in focus order.
      *** POTENTIAL INCOMPATIBILITY with Tk 4.0b2, but not with Tk 3.6 ***
    - Eliminated tk_focusContinue.
      *** POTENTIAL INCOMPATIBILITY with Tk 4.0b2, but not with Tk 3.6 ***

3/8/95 (new feature, bug fix) Added support for tk_strictMotif variable
in C:  Tk_StrictMotif library procedure.  Modified buttons, menubuttons,
menus to use it.  This fixes the problem with menus not supporting
tk_strictMotif properly in Tk4.0b1 and b2.

3/16/95 (feature overhaul) Overhauled color management:
    - Changed Tk so it never denies a color request because a colormap
      filled up.  Instead, it allocates the closest available color.
    - Eliminated "color model" mechanism.  The "tk colormodel" command
      is gone, as are the procedures Tk_GetColorModel and Tk_SetColorModel.
      *** POTENTIAL INCOMPATIBILITY ***
    - Changed 3D border implementation to allocate colors for shadows
      lazily, so they're never allocated if they're never used.  Also
      added new feature whereby stippling is used for borders when
      the colormap has run out of entries.  Changed arguments to many
      of Tk_3D C procedures to take a Tk_Window as argument instead of
      a (Display *).  This is needed to do lazy color allocation.
      *** POTENTIAL INCOMPATIBILITY ***
    - Eliminated colormap argument to Tk_GetColor, Tk_GetColorByValue,
      and Tk_Get3DBorder.
      *** POTENTIAL INCOMPATIBILITY ***

3/16/95 (feature change) Event bindings created from Tcl will now ignore
Enter, Leave, FocusIn, and FocusOut events with detail NotifyInferior.
This is done in anticipation of mega-widgets, so that the user of a
mega-widget can create Enter/Leave bindings on the mega-widget without
seeing spurious events as the mouse moves among the windows in the
mega-widget.
*** POTENTIAL INCOMPATIBILITY ***

3/17/95 (feature change) Changed C interfaces throughout Tk to use ints
instead of unsigneds:  the unsigneds turn out to cause subtle problems
with arithmetic in some places, and using ints everywhere is just
simpler.
*** POTENTIAL INCOMPATIBILITY ***

3/23/95 (bug fix) Selections longer than 4000 bytes were being
truncated to 4000 bytes.

-------------------- Release 4.0b3, 3/24/95 -------------------------

3/25/95 (bug fix) Changed "install" to "./install" in Makefile so that
"make install" will work even when "." isn't in the search path.

3/25/95 (bug fix) Modified Tk's selection mechanism to prevent core
dumps in other applications during retrievals of large selections
(this is actually a bug in the other apps, but I've patched Tk to
keep it from getting triggered).

3/25/95 (bug fix) Fixed bug where X window for "." wasn't being
deleted.

3/27/95 (bug fix) Fixed many bugs associated with having more than
one application in a single process.

3/28/95 (bug fix) The "search" widget command for texts didn't
return the correct index and count if there were embedded widgets
on the same line as the returned range but before the end of
the range.

3/28/95 (bug fix) Changed pasting via button 2 in text and entries
so that it inserts at the pointer location, not the location of
the insertion cursor.

3/28/95 (bug fix) Fixed several bugs related to <Destroy> bindings
that delete ancestors in the window hierarchy.  Also eliminated
extraneous calls to XDestroyWindow, which speeds up window deletion
by about 3x.

3/28/95 (bug fix) Several widgets (buttons, menubuttons, menus) didn't
properly handle image deletions that occurred while the widget was
being deleted (caused core dumps).

3/29/95 (bug fix) When retrieving long selections from text widgets,
parts of lines were getting duplicated in the selection information.

4/1/95 (bug fix) Fixed bug that caused infinite loop in horizontal
scales with 0 range.

4/1/95 (bug fix) Fixed problem with -command option for scrollbars and
-takefocus option that caused commands to be evaluated in the wrong
context.

4/1/95 (bug fix) Fixed problem with option database that caused it to
sometimes use the wrong option (wasn't flushing the database properly
after a change in a window's class).

4/1/95 (bug fix) If a line in a text widget just barely fit in the window,
Tk was allocating a second screen line just for the newline character.

4/1/95 (new feature) When backspacing in an entry widget, when you reach
the left edge of the widget, the insertion cursor gets recentered.

4/1/95 (new features) Added "winfo pointerx" and "winfo pointery" commands
to fetch the current pointer position.

4/6/95 (bug fix) If the last line of a text widget was only partially
visible, it was counted as visible for purposes of the scrollbar.  Now
it is treated as if it were off-screen for scrolling purposes.

4/6/95 (new feature) Modified "bell" command to reset screen saver as well.

4/6/95 (feature change) Modified menu scanning (where menus pull down
as you drag across their menubuttons) so it only works among menus
in the same toplevel;  it used to work for any menubuttons in the
application.

4/6/95 (bug fix) Canvas text items weren't allowing real numbers in
"@x,y" notation for specifying indices.

4/7/95 (bug fix) Menus didn't display correctly when -activeborderwidth
was large.

4/7/95 (bug fix) Changed "clipboard append" command to support -- option
and to always treat the last argument as data, even if it starts with
"-".

4/17/95 (new feature) Added -wrap option to text tags.

4/18/95 (bug fix) Listboxes and texts weren't updating their grid information
when -width or -height changed.

4/18/95 (bug fix) "Down" didn't work right in text widgets if the last
line was only partially visible in the window.

4/19/95 (bug fix) Listboxes didn't handle partially visible last lines
right:  couldn't scroll it into full visibility, for example.

4/20/95 (bug fix) If a toplevel was positioned with a command like
"wm geometry . -0-0", the window didn't reposition itself to maintain
that geometry after a size change.

4/21/95 (feature change) Changed order of binding tags so widget bindings
fire before class bindings.  New order is: widget, class, toplevel, all.
*** POTENTIAL INCOMPATIBILITY with Tk 4.0b3, but not with Tk 3.6 ***

4/23/95 (new feature) Added "winfo colormapfull" command.

4/23/95 (new feature) Buttons and radiobuttons and checkbuttons now
treat Return the same as Space, unless tk_strictMotif is set.

4/23/95 (bug fix) Modified menu tear-off procedure to duplicate the
binding tags and bindings of the original in the copy.

4/25/95 (bug fix and feature change) Modified mechanism for choosing
"best" visual to fix a bug where depth wasn't really getting highest
priority in all situations.

4/28/95 (bug fix) Failed text searches starting at "end" could result
in an infinite loop in Tk.

4/30/95 (new feature) Added "wm resizable" command to enable and
disable interactive resizing.

4/30/95 (new feature) Added "window names" widget command to texts:
returns a list of all embedded windows.

5/2/95 (feature change) Changed text searches so that forward searches
start at the given index, rather than the character just after the
given index.
*** POTENTIAL INCOMPATIBILITY with Tk 4.0b3, but not with Tk 3.6 ***

5/4/95 (bug fix) Default bit gravity for windows was wrong (it was
ForgetGravity) causing unnecessary flashing when windows were resized.

5/4/95 (feature change) Modified Tk_DoOneEvent so that it doesn't
sleep if there's nothing that will wake it up again (e.g. no file
or timer handlers).  Returns 0 immediately.

5/5/95 (configuration change) Changed to use BSDgettimeofday instead
of gettimeofday on systems like IRIX where BSDgettimeofday is
available.  This avoids compilation problems due to the different
interface to gettimeofday provided by IRIX.

5/5/95 (feature change) Changed binding mechanism so that all bindings
are created immediately at initialization time, rather than waiting
until the first FocusIn or Enter event for a class.

5/6/95 (feature change) Changed default text for labels, buttons,
checkbuttons, radiobuttons, menubuttons, and messages from " " to
"".

5/6/95 (bug fix) If the application was destroyed in the middle of
an "update" command, Tk would dump core.

5/6/95 (bug fix) Changed manual entries to use the standard .TH
macro instead of a custom .HS macro;  the .HS macro confuses index
generators like makewhatis.

5/6/95 (bug fix) Change "wm iconwindow" command to disable button
presses for the icon window.  This is needed so that the window
manager can get those events (X only allows button presses to go
to one client for a given window).

5/9/95 (new feature) When specifying visuals, can now use "best"
with a depth, e.g. "-visual {best 8}" to get the best 8-bit visual.

5/18/95 (bug fix) Fixed bug with -spacing* options for text widget:
screen distances weren't allowed, only integers.

5/20/95 (bug fix) Eliminated memory leaks in tkTextDisp.c and elsewhere.

5/22/95 (color change) Changed the Tk color palette to a gray scheme.
Also added a library procedure tk_setPalette that makes it easy to
change colors on the fly, and a procedure tk_bisque that restores the
previous light brown scheme.

5/28/95 (bug fix) Modified canvases so that the -width and -height
options refer to the space inside the borders, not the total widget
space.  Also changed "xview" and "yview" commands and scroll-increment
rounding to use the pixel just inside the borders, rather than (0,0).

5/28/95 (bug fix) Several widgets (e.g. entries, buttons, and menus)
didn't properly handle unsets of variables they were tracing, if the
variables were reference through upvars in procedures.

6/4/95 (bug fix) The placer wasn't rounding window widths right when
both -relx and -relwidth were specified (or -rely and -relheight) so
that rounding errors accumulated.

6/4/95 (feature improvement) Change parsing of text indices to handle
weird mark and tag names better (e.g. any string ending with ".first"
will now be parsed as a tag name, even if it contains embedded spaces,
etc.).

6/4/95 (feature change) If a font defines glyphs for control characters,
they are now displayed, instead of translating the character to a
backslash sequence (however, tabs and newlines are still treated
specially;  glyphs are not displayed for these characters).

6/4/95 (bug fix) Modify the implementation of "raise" and "lower" for
toplevels so that it now works under olwm and olvwm.  It didn't use to
work, and the problem is really in the window manager, but Tk now
patches around it.  However, only "total" raises and lowers work:
raising and lowering relative to a sibling still don't work under
olvwm and olwm.

6/4/95 (feature change) Modified tab code in texts so that a tab always
occupies at least as much space as a space character.

6/4/95 (bug fix) The "%t" substitution wasn't being made properly in
Enter and Leave event bindings.

6/7/95 (new feature) Added support for GIF images.  Unfortunately it's
a bit fragile:  certain kinds of badly formed images can cause core
dumps;  I don't know enough about the GIF reader (taken from giftoppm)
to figure this out.

6/7/95 (bug fix and feature change) Fixed PPM image reader to be more
flexible about header formats, and added support for PGM images.

6/7/95 (feature change) Added -outlinestipple option to canvas arc
items, changed "-style arc" to use -outline as the color instead of
-fill (the old approach was pretty quirky).
*** POTENTIAL INCOMPATIBILITY ***

6/8/95 (feature change) Modified interface to Tk_Main to pass in the
address of the application-specific initialization procedure.
Tcl_AppInit is no longer hardwired into Tk_Main.  This is needed
in order to make Tcl a shared library.

6/8/95 (feature change) Modified Makefile so that the installed versions
of wish and libtk.a have version number in them (e.g. wish4.0 and
libtk4.0.a) and the library directory name also has an embedded version
number (e.g., /usr/local/lib/tk4.0).  This should make it easier for
Tk 4.0 to coexist with earlier versions.

6/9/95 (new feature) Added -outline and -width options to canvas polygon
items.

6/9/95 (feature changed) Renamed -decimate in photo widget to -subsample
(decimate wasn't technically correct).
*** POTENTIAL INCOMPATIBILITY with Tk 4.0b3, but not with Tk 3.6 ***

-------------------- Release 4.0b4, 6/16/95 -------------------------

6/19/95 (bug fix) Colors weren't being rounded correctly in canvas
Postscript generation: caused "white" to appear slightly gray when
the display of the canvas used only 8 bits per color.

6/20/95 (bug fix) "bbox" widget command for texts didn't return
proper width for tabs.

6/20/95 (bug fix) Scrollbars didn't always work right for texts:
couldn't scroll all the way to the bottom of the text in a single
drag of the slider.

6/20/95 (new feature) Added "delta" widget command for scrollbars
(needed for above bug fix).

6/23/95 (bug fix) Listboxes weren't properly redisplaying their
borders when the were configured to a smaller size.

6/23/95 (new feature) Added "winfo server" command.

6/23/95 (bug fix) If a menu was posted, couldn't switch to another
menu with an Alt- key.

6/24/95 (new feature) Added "winfo pointerxy" command.

6/25/95 (bug fix) Tk_ParseArgv referenced beyond the end of 0-length
option names.

6/25/95 (bug fix) Fixed problem in tkOption.c where "cachedWindow"
could get garbage in it if the main window's class was changed by
calling Tk_SetClass.

6/25/95 (bug fix) Fixed two bugs in menus, one where errors in
variable traces weren't propagated correctly and one where "invoke"
was invoked at the wrong stack level, with the result that variable
traces didn't have access to the right variables.

6/27/95 (bug fix) tk3d.c wasn't using all the right information
when deciding whether or not to stipple borders, so it stippled
borders even on 16-bit true-color displays.

6/28/95 (bug fix) Page up and down operations in texts could cause
insertion cursor to drift to the right.  Changed tkTextScrollPages
to use upper-left corner of current character, rather than center
of character.

6/28/95 (bug fix) Changed text widget so that you can't put the
insertion cursor after the last newline in the text.

6/28/95 (bug fix) Bitmap images didn't allow ~'s in file names.

6/28/95 (bug fix) Fixed problem that could cause core dumps in the
text widget when dealing with embedded windows (there were problems
if the act of redisplaying caused the window layout to change, which
can happen with embedded windows).

6/28/95 (bug fix) Texts didn't handle indices with double negatives,
such as ".t mark set insert {insert + -20 chars}".

6/28/95 (bug fix) Fixed problem where focus didn't always revert to
its prior window after a dialog box was dismissed.

6/28/95 (bug fix) Fixed problem with "search" widget command returning
incorrect length on some backwards regexp searches.

6/28/95 (bug fix) Successive "wm iconbitmap . {}" commands could cause
a core dump.

6/29/95 (new feature) Added -elementborderwidth option for scrollbars
so the -borderwidth can be set to 0 without flattening the arrows and
slider.

-------------------- Release 4.0, 7/1/95 -------------------------
