LIOS drop-down menu entries are accessible with the Alt key:
Alt+F File
Alt+E Edit
Alt+I Image
Alt+S Scan
Alt+S Recognize
Alt+T Tools
Alt+P Preferences
Alt+H Help

From the menu, you can navigate with the arrow keys.

Some commands have a key binding, indicated alongside them.

To know more, read one of the user guides provided in this directory in
various formats.