Identify snapped windows independent of screen
--the old code wasnt screen independent for identifying
windows that touch the panel edge. There were cases
that when a window was touching a panel edge at
screen A to faulty identify that is touching
screen B also. The code now is more robust and it
can also handle cases that window is touching two or
more different panels in different screens.
BUG: 397076
FIXED-IN: 0.8.1
(cherry picked from commit 7bceb7e4b752955c0a9be79f57b0485c9271e1ef)