While trying to add timidity-gtk as an automatic opening option in Gnome Commander,
I realised that the Change button in File Properties after Open With: does not work.
The default Banshee settings does not open .mid files.
Same with other file extensions: eg. F-Spot for jpg files, no change option available.
In the meantime, Nautilus allows change Open With properties easily.
Is this the standard feature of Gnome Commander, or some settings /adds-on are required?