I have not figured out an efficient way to select planes from parts when trying to mate in an assembly specifically ones with subassemblies.  I can select a part in the graphics view, it will scroll to the part in the FM tree and i select the plane i want from that part.  From there i select mate which causes the flyout FM to appear.  From here i need to find another base plane from a different part.  I would like the ability to do a scroll to the second part on the flyout FM.  Is there a way to do this?