I have a table, where a field called disadvantages is linked to a second table with the same name. The field allows multiple entries. I also have a form based on the main table. Is there a way I can make the form based on the main table, open a new popup subform when someone types a new entry into the disadvantages field, that is not already on the disadvantages table. (The form I want to open will be linked to the disadvantages table, and will effect allow the user to add thier own disadvantage to that table). I know it can be done with a button, but I want to know if there is a way for the form to realize the tyed entry is new and automatically open the disadvantage form.