I should be able to see the property value that I am overriding

(User Story, Investigate , Priority: High, Test Status: No automated tests yet , Reported By Justin du Coeur, )
Editor
Summary: In the Advanced Editor, show the inherited value, with some highlight / lowlight that indicates that it is inherited. Any change automatically makes it overridden. Trash / Revert then becomes available, although probably requires two clicks.
This might want to also be true in the Instance Editor, but think about the UX carefully.