http://bugs.winehq.org/show_bug.cgi?id=17215
--- Comment #30 from Johan Gill johan.gill@gmail.com 2010-03-23 10:49:28 --- Ok, I've solved my testing problems, so here are some results:
Setting the cooperative level back to DDSCL_NORMAL does NOT restore the display mode.
However, releasing the ddraw interface does restore the display mode
Exiting an app without releasing the interface also restores the display mode