( See Also: Middle click folder to open in new folder tab )
If you only ever want to have a single Opus window open then the following options will help.
Note that the first two screenshots are not the same, one is for Desktop Double-click and the other is for Taskbar Icon Double-click.
If you turn on these options then you may also want to turn on the option to quit Opus when all windows are closed. That is covered in a separate FAQ.