Horse inventory doesn't work properly

When I try to open my inventory on a horse, I only get a solid grey screen.  Pressing E or Esc closes it, but I can't do anything on it (put on a saddle, put on armor, etc.)  Not sure if this has anything to do with running the Linux version.

 

EDIT, just realized that the screenshots don't show the same issue.  It must be a rendering issue.  Leaving it open.  I will try to get a screenshot of the blank screen I get.