I notice that a File/Folder Filter on a floating toolbar does not interact with the SOURCE lister, or indeed any lister if more than one is open. A bug, perhaps, or is there a reason why filtering this way is not possible when the toolbar is floating? It certainly works OK when the toolbar is fixed.
I think certain things are that way by design... it works when the toolbar is fixed to the lister because then there's no question which lister it should apply to.
Right, but the same argument could be applied to many Opus commands that work perfectly well from a toolbar whether it is fixed or floating. My tests indicate that such commands operate on the SOURCE lister if there is more than one open. For example, as a simple test, I created a button that toggles MD5 Checksum display.