auto-create a "blank task panel" when i resize the up task panel, a false panel create back, need use xkill for kill the "ghost" panel
I had something like this too. I realized it was a stale default session that was trying to start xftaskbar4. That's the first thing I'd check.
I have the same kind of problem : after switching to xfce 4.3.90 beta2, I now have at startup a ghost panel larger than my panel under the bottom panel, and it vanish 3-4s after the startup. Don't know what to check
'pkill xftaskbar4' from a terminal. Or, better yet, actually uninstall the old Xfce first...