Please describe the problem:
I use Xinerama with two monitors next to each other horizontally.  Sometimes I
want to Alt+drag a maximized window from one screen to another.  If I drag the
mouse exactly horizontally, nothing happens until I move it a bit vertically
(either up or down).  Then the window becomes no longer maximized, and I can
drag it -- but the mouse cursor is way outside the window borders.

Steps to reproduce:
1. Use Xinerama with one screen LeftOf another screen.
2. Maximize a window on one of the screens
3. Position the mouse cursor in the middle of the window
4. Press Alt and hold down the mouse button.  The mouse cursor changes to a cross.
5. Move the cursor horizontally to another screen as far as possible.  Try to
keep it in one line (moving it a few pixels up or down doesn't change the behaviour)
6. The window is still its original position.
7. Now move the mouse up or down about 50-100 pixels.


Actual results:
The windows becomes normal-sized and follows the mouse movement -- but it does
so far away from the mouse cursor.


Expected results:
I would expect the window to become unmaximized and start tracking the mouse
movement when I move it those 50--100 pixels in any direction, not just in
vertical direction.

Does this happen every time?
Yes.

Other information: