GTK is short for the Gimp Tool Kit
These libraries along with GDK and the Gnome libraries are the foundation of your gnome install. You may run GTK based applications without gnome but once applications are tied into the gnome libraries you may not readily run them without the gnome libraries installed.
For a more complete (and authoritative) explanation please see:
The GTK Website at http://www.gtk.org.
The Gnome Developers Resource base via the Gnome Web Site http://www.gnome.org
GTK allows developers to integrate many features into your Graphical User Interface.
Not withstanding features like themes, default icons and window decorations the ability to alter / configure shortcuts and move and tear away menus can be productive and fun.
Here is how to :
Reconfigure Shortcuts, read Section A.2.1.1
Break Away Menus, see Section A.2.1.2
Move Menu Bars, refer to Section A.2.1.3
Any sub-menu (flip out) menu item may have its shortcut altered from the default by simply leaving the mouse pointer over that item and entering the new shortcut. You don't have to press the control or alt (meta) keys as well, just any key not already being used in that particular menu.
Create a floating version of any menu by doing the following:
Open a menu from the tool-bars:
Does it have a perforated line across the top of the functions list? If Yes just click on that line... and you now have a floating menu that you can move about wherever you need.
To close this menu click on the arrow on the left hand side at the top of the menu. Or use your window manager controls on the window border.
Sometimes you just need or want too many tool-bars open to sensibly fit at the head of the Application Window..
Left Click over the raised (and textured) area at the left of the tool-bar you want to move. Now Drag it anywhere you like including onto your desktop. Often you can drag it to the side of the Application Window and have it set up running vertically down the side of the Main Window. Some "apps" remember all of this as well.
The results may not be what you expect but then play is an important part of learning for most mammals so .. have a go........!