Let's say I have a corner panel along the top of my desktop, so it's
horizontal.  And I only have a few launchers in it, so it's really small. 
Now, even though the panel is really small, it essentially consumes the
entire top edge of my desktop.  I am unable to move windows to the top of
my desktop because the panel is "blocking" them, even though I'm moving the
windows to an area where the panel does not exist.  This sucks.