Version: KWin 3.0 from KDE 3.2.2 / Qt 3.3.1 (using KDE KDE 3.2.2)
Installed from: SuSE RPMs
KWin's Xinerama handling could be improved a bit by adding a new feature:
a user configurable key and a window / window menu feature should allow a window to be expanded in size to fill the whole desktop instead of a single xinerama screen.
This would be especially useful in Konsole when invoking vimdiff :-)
For konsole I did the following:
a) bind F11 to fullscreen
b) remove window border
c) expand to maximum
d) increase size to fill both xinerama screens
e) save window settings
Now I can use F11 to switch konsole's size between single screen and all screens.
Since this is not only useful for konsole but for other apps (umbrello for instance) as well, I reported this against kwin.
I suggest to give this low priority, since it can be emulated using the expand window keyboard shortcuts.
I prefer have 2 bouton in title bar for expand, one for only one screen and other for all screen
KWin in 4.9 includes an optional script to create a "videowall", that is make fullscreen video players go over all screens.
Implementing a script to cover the functionality requested in this feature request is fairly simple and due to that I consider this request as implemented.