Maybe Craigs code in this post gives you a start
http://www.sweetpotatosoftware.com/SPSBlog/PermaLink,guid,cbe94fe8-cf6b-4600-9a05-b23b0adff749.aspxLuis Navas
>How can I do to show a message "Object class is invalid for this container" at design time when a control is added to a toolbar (the same way VFP does when you try to add a control to an invalid container)?
>I've created some classes and I would like that it only be used in forms, not in toolbars.
I never forget a face, but in your case I will make an exception :-)
