What I have done that seems to have worked. Hooked up a dual monitor. Changed the resolution for each by going to lower resolutions. Moved SU to secondary monitor. Expanded SU to Maximize. Made secondary monitor the only display, opened SU. Changed worked space preferences by UNchecking Use Large Tool Buttons and later rechecking them, deleted all my custom trays and then created a new one, Switched display back to both monitors and changing the Display Resolution of both back to their “Recommended” settings (1920 x 1080), and Unchecked both boxes for Graphic Settings and later rechecked them.
Results:
I can now double-click on the Title Bar of the custom tray, the Pin appears and by clicking on it, the tray docks.
The only the that does NOT work is getting the docking Symbols to appear.