How to prevent program windows from being moved under a desktop toolbar?

Question

I have no idea what the feature I'm wanting is called, so I'll just describe it. Under linux gnome there is a system toolbar that runs (by default) across the top of the screen. Now, if you try to move a program window over this toolbar it stops just under the toolbar. You can move the mouse pointer over the toolbar but the program window will not follow any higher. This is like "always on top" but adds the feature that windows cannot be placed under it.

My question is how is this done? Is it the window manager doing this? And can this be do using Java or do I have to use xlib?

Thanks.

Answer 1

I've found the solution. The window manager property _NET_WM_STRUT_PARTIAL reserves space for the toolbars. This space cannot be used by normal windows and so by setting this property other windows cannot be moved over or under the toolbar (Just like the gnome 2 toolbars in redhat).