Hi Tim,

When you subclassed the control, did you name it PreferenceForm also? When we subclassed the LoginForm for our apps, we named it LoginForm. We then removed the LoginForm that comes by default, and added a form called LoginForm based on our new class.

One other thought, have you modified classes.dbf at all? Is it possible that there is a misspelling on the form name?

I hate to ask this question, but is the class library where the subclassed form resides a part of your app?

HTH,
Brian