Taskbar with size of 16 pixel got a little line at ground, that makes by clicking with mouse, to send the taskbar into background. -> Screenshots http://frank.uvena.de/tmp/before.jpg http://frank.uvena.de/tmp/after.jpg
I'm sorry, I don't understand your bug report. All I see is a panel with auto-hide enabled, what else are we supposed to see here?
It's hard to discrbe. Have a look to the taskbar on top of the screen. there is a small line, about 1 or 2 px. If I click to it, the taskbar gets covered by a grey bar. To get them back into the foreground, I have to go to the preferences of this bar and high the size.
You just have an instance of xftaskbar4 or xfce4-iconbox running from your old xfce 4.2. Kill them and restart xfce, saving your session.
This should probably become an FAQ when 4.4 finally gets released