Gnome Menu and any icon at the "Taskbar" vanished after the update on 25th march

On Monday, the 25th March the update manager popped up and asked me to install some updates, I completed the update process, rebooted the PC and my menu in the "task bar" was gone.

I still can see my desktop with all relevant icons but the Trisquel logo in the lower left, which ususally launched the app menu is completely gone.
Also any symbol such as the audio mixer vanished.

Removing ~/.config/dconf/user helped. After reboot I had my menu and icons in the task bar again.