A new custom property "AllowEdit" with the default false will allow to edit properties.
If set to true there would be an edit button or on double click on the values it would show the value in a multi-line edit box with a little check and x image on the side or below so one can then edit that value(s). Once a value has changed a little save button appears in the top menu (or the check x combination). This way one can change multiple properties before saving back.