Contact selector: hide right-click menu if no entries

Currently, when there are no entries in the right-click menu in contact selector (use case: search in trash (deleted contacts)), we still override the right click on the contact name. As there are no entries in the right-click menu, the only thing that shows is a small, black nine-pixel triangle.

Solution: when the right-click menu is empty, either do not override the right click at all or show nothing (not even the small triangle).