gtk+3: gtk+3 (multi-platform GUI toolkit) gtk+3: gtk+3: This is GTK+, a multi-platform toolkit for creating graphical user gtk+3: interfaces. Offering a complete set of widgets, GTK+ is suitable for gtk+3: projects ranging from small one-off projects to complete application gtk+3: suites. gtk+3: gtk+3: gtk+3: gtk+3: gtk+3: