I switched from gnome to xfce4.10 (debian using siduction) and most things seem work fine. Still some problem with my dual monitor setup with two separate display (:0.0 and :0.1 - which allows me to have separate workspace/viewports on each monitor).
* Notification area / systray can't be added to second display/screen
Even though the systray plugin is marked with "X-XFCE-Unique=SCREEN", panel still wouldn't allow me to add systray to second monitor
I've tried manually starting the panel add dialog on second screen, but it still doesn't work:
xfce4-panel --display=:0.1 -a 3
Without second notification area, I couldn't start another clipman (which would quit soon after start)...
* Clipman plugin is marked as unique
This prevents two clipboard manager running to share/sync clipboard. I found a workaround though:
1. start xfce4-clipman in first screen
2. add xfce4-clipman-plugin to second screen
Submitted bug for notification area problem: https://bugzilla.xfce.org/show_bug.cgi?id=9838