Provide in the ribbon a button to pop up a list of planes.
Reason: When I have many planes, or even two at the same location, it is hard to select the desired plane. If they each had a number and were in a list (the list should show the normal vector too for identification) it would be easy to select the intended plane. The list should allow you to add/delete planes directly.
Further enhancement: allow user to copy existing planes with settings intact.