ok, there's one i would never have found... as i use my right hand for the mouse and hitting pause.

the issue is that when you left+right click to move, blizzard moves the cursor outside and to the left of the screen putting itself in mouse-input sort of mode (same with camera view). when you hit pause, that momentarily broke the mouse capture to the wow window... and that's when things got messed up. the wow window is looking for a mouse up event, but since it won't let you in to click, you can't do it (you can if you are quick).