Description of Problem:

Attempts to drag a window in "Workspace Switcher" display to another workspace
sometimes succeed and sometimes not.  It is always ok to drag a window to
an "active" workspace and you have a pretty good chance of success if this
is done to a some "remote" workspace.  If you will do that to one of
"neighbours" of an active workspace then you are playing a game of chance
with a pretty good probability that a dragged window will "jump" back 
to its original position but it will likely get "lost" and has to be
"re-dragged" again to an active workspace before showing up.  If this happen
then the window will be also lost on a window list on a panel.

This "jump-and-loose" may be easier to observer with sawfish.  Windows are
not lost on a "Windows" sawfish menu (middle mouse button).  Opening
a window in another workspace and later switching back to a messed up one
seems to restore sanity on a panel.

Attached is a screenshot with three terminal windows and only one entry
on a windows list.