It turns out /dev/nvidia-modeset is a red herring. If I add the following line to /etc/apparmor.d/local/usr.bin.firefox:
/dev/shm/org.chromium* rw,
the refresh problems disappear.
It turns out /dev/nvidia-modeset is a red herring. If I add the following line to /etc/apparmor. d/local/ usr.bin. firefox:
/dev/ shm/org. chromium* rw,
the refresh problems disappear.