I see what the problem is. From the help:
The code in an Assign method is executed when you attempt to change the value of a property, typically by using the STORE or = command to assign a new value to the property.

Assign won't fire unless the value is changed programmatically, so just clicking on the tab won't fire it.

>Simple form with no code and just a 2-page pageframe. To change the pages, I am clicking on the page tabs. When you used code in a command button, would that be an example of _Access instead of _Assign?
>
>All I have in the ActivePage_Assign of my baseclass is:
>
>

LPARAMETERS vNewVal
>*To do: Modify this routine for the Assign method
>THIS.ACTIVEPAGE = m.vNewVal
>debugout "assign fired..."

>
>I drop the class on a form, save, run. I add no code to the class on the form. I never get output to the debugout window.