Dialog to access/open folder/file = total system freeze

R studio is properly installed and seems to work great in all contexts, except when I try to use the standard dialog for opening a folder, file, or any other operation that accesses the file system. When doing so, everything ... the entire system, computer, etc. ... freezes. Is is possible that the computer would eventually respond, but during the freeze processor activity seems to peak because my fans all turn up. That leads me to abort by going to a new virtual terminal, (which does work), signing in, and forcing a shutdown or reboot.

This happens with the most current version of R-studio, RStudio 1.2.5001 - Ubuntu 18, as well as well as the bleeding edge version.

The Linux desktop I'm using is Ubuntu 18.04.3 LTS bionic, which is fully updated/upgraded.

Any suggestions would be much appreciated!