Removal of Upper support for Z axis rods

Does anyone know how to remove the top support for the z axis rods from the black panel on the R2?
It seems to have a screw holding it to the back panel. It will tilt slightly with pressure, rotating around where the screw seems to be. It does not seem to be held by a clip but nothing else makes any sense.
thanks

 

The plastic part that sticks out from the black background part has two screws which come out easy. But there is something else holding the two black parts together. I assumed some kind of sliding clip but wasn't able to get anything to move.
once the part that holds the rods is off, the screw that holds the black back to the white frame should be easy to reach.
so far no luck.
j