after turning off 3D effects by pressing Alt+Shift+F12, I cannot turn it
on again. The shortcut for this is called “Suspend Compositing”, which
sounds like it can be turned off only. This used to be a toggle switch
before KDE 4.2 release.
Does anybody know how compositing can be turned on again after switching
it off using Alt+Shift+F12? Logging out and in isn’t much of a pleasant
option here.
Did you try desktopsettings central configuration module?
Otherwise you can right click on the top border of any open window then go to “configure desktop settings” (or something simila, i’m not currently on kde4). There you should be able to configure composition.
i would say IMHO that theres something wrong with or they have changed something with 4.2 cause i was using the toggle compositing plasmoid and it isn’t working either since i upgraded to 4.2 but it was working in 4.2rc1