Hello, after latest update, in Firefox, the dropdown "open containing folder" does nothing.
The latest Opus update or the latest Firefox update?
After a fresh install of Windows, Firefox, Opus and nothing else, the issue persists.
Firefox opens things in Opus OK here, with the latest Firefox and Opus (12.29).
Make sure Opus isn't running elevated. Other than that, if no other software (not even antivirus etc.) has been installed then I don't have any ideas as that's the same setup as my test machine.