Another Debian bug reference ( #1002725) provided a better (for me!) clue:
In /etc/apparmor.d/usr.bin.evince adding after /usr/bin/pcmanfm Cx -> sanitized_helper, # LXDE /usr/bin/krusader Cx -> sanitized_helper, # KDE /usr/bin/thunar Cx -> sanitized_helper, # XFCE the line /usr/lib/x86_64-linux-gnu/libproxy/0.4.17/pxgsettings Cx -> sanitized_helper, # Print Dialog
After restarting apparmor, the print problem was fixed
Another Debian bug reference ( #1002725) provided a better (for me!) clue:
In /etc/apparmor. d/usr.bin. evince bin/krusader Cx -> sanitized_helper, # KDE lib/x86_ 64-linux- gnu/libproxy/ 0.4.17/ pxgsettings Cx -> sanitized_helper, # Print Dialog
adding after
/usr/bin/pcmanfm Cx -> sanitized_helper, # LXDE
/usr/
/usr/bin/thunar Cx -> sanitized_helper, # XFCE
the line
/usr/
After restarting apparmor, the print problem was fixed