I usually have multiple Firefox windows open and because of limited screen space they are often tucked behind other windows with only a corner showing. It would be very helpful if there were small regions in the corners of the Firefox windows that would highlight when hovered over, and that would bring the window to the front when clicked on. (The corner I most often seem to have peeking out is the upper right, and unfortunately, it does the last thing I want: it closes the window.) These regions could be very small, just little colored triangles. They could even go away when the window was not occluded so they wouldn't interfere with normal use in any way.
Thanks,
Charles