Gary, all, My Polymorph-based image mask editing gizmo is taking shape. I easily set up a column of buttons to clear, save and toggle display of the mask. I had a pretty rough time making the toggle *work* but that was a logic error on my part. Next, I need to detect that a mask has been saved and apply it to a newly loaded image; I think I see how to do that. Another important feature would be to automatically save the mask rather than expecting the user to do that explicitly. How can I detect that the morph/panel is about to close and execute a command? If I wanted to do so, how could I detect that the mask has not been saved, and warn the user and/or veto closing the morph? For now I would be happy to just save the mask, but stopping something from closing will eventually arise. Bill