Hello,

like the title suggests it's not possible to use alt-tab to switch from a fullscreen game to the desktop.
The game loses focus, the desktop is shown, but it no longer responses to any input. The only solution is to kill the application from another session.

I'm using the latest proprietary ATI driver and latest KDE.

It does apply to all kinds of games (native or run through wine).

I'm not knowledgeable enough to see whether this is a bug or not. I'll try to ask some KWin developers.

When asked on the matter, the KWin maintainer said that the issue does not originate from KWin, but rather from the game itself.

Not all games behave this. For those that do, even changing the volume with kmix in-game (which causes the OSD to appear) can cause the game to poo poo. That's a serious issue.

However the issue is in the game, and not in KWin, and as such, I don't think there's much the KWin developers can do about it.