No Item to Display but only when I run the App

[Anonymous]

Thanks. That solved my problem too. 
One addition: to work, the record specified in the item property of the form has to match the fields added in the edit field of the connection of the form. In other words, it seems that I need to add always all the fields in the form to be able to have it working.
So I am making not visible the fields of the record that do not need to appear in the forms.