After unchecking (by accident) and later on checking again the entry "Network Manager" in the Application Autostart tab of the Session and AUtostart session, Networkmanager does not appear any longer in any tested DE (Xfce 4 and also KDE is affected). Reason for that is that uncrossing the Networkmanager box creates a desktop file in ~/.config/autostart containing a line "Hidden = true" which does not get removed or modified if the nm box is checked again. Hence, nm-applet icon disappear from all the notification areas, making it very it impossible to connect to the network the nm-applet.
This is on openSUSE 11.4 and xfce-session version 4.8.1
Can't dupe this here (Gentoo, xfce4-session 4.8.1). Toggling the checkboxes modifies the .desktop files in ~/.config/autostart/ as expected for me.
Hmm, strange I cannot reproduce that bug any more. The "Hidden= " entry in the desktop file now switches as expected. I guess the bug can then be closed or marked as invalid. Thanks for the response anyway!