http://bugs.winehq.org/show_bug.cgi?id=14034
--- Comment #10 from Tobias Jakobi liquid.acid@gmx.net 2008-07-31 12:46:58 --- Update:
The mirror issues with ORM=backbuffer (mirror not working from all angles, black bars are visible inside the mirror) is directly tied to bug #14686.
As soon as an ingame resolution with a POT component is selected the black bars disappears and the mirrors work/look like they should.
Seems like that the scene image displayed in the mirror is suffering from the same cropping issue.
Greets, Tobias