I've just purchased a Gigabyte M6880 laser gaming mouse and it seems to randomly change DPI in World of Warcraft for no reason. There's a button on the mouse for changing the DPI from 800-1600 but I never press it, it just seems to change for no reason. World of Warcraft is the only game I play where this problem occurs. In other games it's fine.
Actually it seems to be whenever I hold down the left & right mouse buttons at the same time (which is "Auto-run" in WoW).
I've just installed some drivers and that didn't help either.
What could be wrong with it?
Thanks.