I had the same problem. Here is a workaround that worked for me:
Install mozilla-firefox first, then install xdm. If you have already installed xdm, remove it, reboot, run firefox, install xdm again. Now you should have managed to run firefox and xdm.
I had the same problem. Here is a workaround that worked for me:
Install mozilla-firefox first, then install xdm. If you have already installed xdm, remove it, reboot, run firefox, install xdm again. Now you should have managed to run firefox and xdm.