After a desktop environment restart (e.g. after a DE crash or by invoking "gnome-shell --replace" in a terminal), the Notification Area Extension fails to detect the newly created system tray. It also happens, if the system tray is started with Banshee already up and running.

This happens in Gnome Shell (and Cinnamon) as well as in KDE.
 It does not happen, if the Notification Area Extension is changed so that it uses the Gtk implementation to communicate with the system tray (usually only used on non-UNIX-systems), instead of its own X11 event handling.

Reproducible: always
How to reproduce:
1) start banshee
2) enable Notification Area Extension (if not enabled)
3) restart desktop environment (e.g. via terminal with "gnome-shell --replace")

Expected result: Banshee recognizes the new system tray and displays its icon there
Actual result: Banshee does not detect the new system, the icon is not displayed

Further information:
The X11 communication in X11NotificationArea.cs gets a wrong selection_atom code from the XClientMessageEvent, although the desktop environment uses the exact same code, that X11NotificationArea.cs uses for comparison. I discovered this when looking into an issue filed to Cinnamon (https://github.com/linuxmint/Cinnamon/issues/1158 and https://github.com/linuxmint/Cinnamon/issues/864)