I seem to remember being able to drag project folders onto the SourceTree application icon in MacOS X's dock, and they would open in Source Tree. This is much faster than finding it in the open dialogue, especially where I can drag the folder icon right from within IntelliJ and don't even need to visit the finder. This feature has been broken for awhile, however. I do not know if it happened when I upgraded to to MacOS X Catalina or when I last upgraded SourceTree. I don't see it mentioned as a known issue, however.
Are there plans to restore this functionality?