Description of Problem: There appears to be no prelight mouseover image for the
Unmaximize Window button
Steps to Reproduce:
1. In Gnome, maximize a window.
2. Mouse over the Minimize Window and Close Window title bar buttons and
observer the nice prelight.
3. Now mouse over the Unmaximize Window and observe no prelight.
Also, this only happens on a maximized window, not on an unmaximized window.
I think this was fixed.