Turns off the second monitor when the game starts, currently the only game I care for is Heroes of Newerth and it doesn't support xrandr, yet.
Originally Posted by adamk
most games don't run well on multiscreen-resolutions anyway. You can however try setting the game to windowed mode and force it into a fullscreen, borderless window. (kwin's application specific rules come to mind, but use whatever your window manager supports)
A RandR 1.2 modesetting backend is coming to the next version of HoN (Just be warned that ATI's RandR 1.2 support has a number of bugs and you may encounter one or two).
Originally Posted by Bruners