Right-click on the owner/group should bring up an context menu with "Change owner"/"Change group" (chown is only active for root, chgrp is active for root and the owner).
(In reply to comment #0) > Right-click on the owner/group should bring up an context menu with "Change > owner"/"Change group" (chown is only active for root, chgrp is active for root > and the owner). I don't like the idea of hiding chown/chgrp in context menus. I think there is a big problem with visibility/usability. It took me some time to discover the context menu, for instance.
Fixed with revision 19357.