>Interesting idea, Mike - but doesn't it add more overhead/upkeep than just using the WHEN in a single control? What advantages would you get?

A true ReadOnly control (being abstract here :-) allows you to enter the control, maybe to select text and copy ect., just not modify the text. With When you can't do that. Say you need doubleclick code in the control, with a When returning .f., I'm not sure that would be possible. Just UI stuff like that.