Those little squares to the left of the combo boxes (one of which has a "pencil" icon in it, indicating a dirty record) are the "record selectors". Clicking a record selector will select the record, then if you hit Delete the record will be deleted.
It looks like you just deleted the contents of the combo box. When you went to save the (still-existing) record Access objected because the .Value
of the combo box was Null
, and your Primary Key on the junction table prohibits Null
values for [model_id].