I keep my working documents in a btrfs filesystem due to the handy "snapshot"'s that I can take once per hour/day/etc.
Neither openscad nor freecad will show the btrfs mounted directory in their "open" dialog. It's just not there, as if it doesn't exist. So far I haven't found any other applications that have a problem with the btrfs mounted directory.
Both openscad and freecad are "snap" apps - but so is firefox and it doesn't have any issue with it. Both openscad and freecad appear to have the same file browser gui - maybe there's something up with it?
Edit: I just removed and installed the non-snap version of openscad and that version works.
thx, tom.c