assertion atom != GDK_NONE failed

[Jochen Roderburg <Roderburg Uni-Koeln DE>]

Hi gtk-experts,

After upgrading glib/gtk to the latest versions glib-2.20.3 and  
gtk+-2.16.2 on a Linux system I keep getting tons of messages from  
Mozilla programs (firefox/seamonkey):

Gdk-CRITICAL **: gdk_x11_atom_to_xatom_for_display: assertion `atom !=  
GDK_NONE' failed

Despite the term "critical" I see nothing wrong in the programs  
themselves, just these messages are cluttering the console window  
where the programs were started.

Best regards,

Jochen Roderburg
RRZK
University of Cologne
Robert-Koch-Str. 10                    Tel.:   +49-221/478-7024
D-50931 Koeln                          E-Mail: Roderburg Uni-Koeln DE
Germany