This could be either a bug in MetaCity WRT panel constraint, or a bug in
Gnome Panel WRT spanning multiple monitors.  Either way, MetaCity still
reserves space for the panel on other monitors -- even when there is
nothing there!

Bug 1: MetaCity improperly constrains edge panels to 1 monitor, ever though
there are 2 monitors.  This causes the "phantom panel" effect where a
maximized window on an adjacent monitor acts like there is a panel there
already (<a href="http://thock.com/broken-panel-scaled.jpg">see
screenshot</a>).

Bug 2: Gnome Panel doesn't have an option to span 2 monitors in Xinerama
mode (Gnome Panel needs enchancement).  MetaCity still doesn't understand
that the panel's only on 1 monitor (<a
href="http://thock.com/broken-panel-scaled.jpg">see screenshot</a>).

If you could let me know wether this constraint to one monitor is the fault
of the WM or a bug in Gnome Panel so I can file another bug, that would be
great.