I have tested adding a additional "line > set > Datepicker" to my field group. When I try it this way, I get the following JS prompts when CSS FB generates the form. See attached JS Prompts.
Once CSS FB is done, the validation sb for the new datepicker has a "!". THen I have to remove that validation code which is screwed up the same way.
Same/similar situation as if I convert an existing form field to a datepicker within CSS FB.
Thanks again for any help. D.