[STUMP] Can't move between frame outside head dimensions

[Mikael Jansson]

I have a 1200x1600 (portrait) head A and to the right a 1920x1200 head B
Xinerama'd together.

If I have a frame at the bottom of head A (say, 1200x200+0+1400), I
can't move to head B. I have to navigate to the frame above and then to
the right.  Moving from B to A always works.

This used to work in 0.9.6, now I'm on HEAD (cde0d26).

-- Mikael