>Initially, I construct a form, with an empty private data enviroment.
>The controls are data bound to a database, not opened yet.
>Then, I use the Load event to open the database and use table.
>This form run OK!
>Then I save this form like a class, and create a form derived for that class. Now, I do form this form, and an error appears! Apparently, something is checking the undefined ControlSources from the databound controls, before the Load event!

My guess is that the parent form object has a different data
session than the child form object. This is why we have to
set the datasession in each form. I guess you could pass the
datasessionid to the parent form. Then your the databound objects
will be able to 'see' your tables.

Ah... Datasessions ...

HTH,

Marc