Thanks for your bugreport.
Do you get a crash file in /var/crash when this happens? If so, could you please geneate a apport report with it. Please run /usr/share/apport/apport-gtk
Thanks for your bugreport.
Do you get a crash file in /var/crash when this happens? If so, could you please geneate a apport report with it. Please run /usr/share/ apport/ apport- gtk