When a user selects a different Supplier from a combo box, I need a pop-up message to display that only 1 supplier per record can be chosen and the same box must give them the choice to create a new record? Any ideas?

Not sure what you mean by the first part of your question.
A Supplier different from what??? Different from the first chosen supplier? If so do you want to prevent the user from changing a supplier once it has been entered?

Regarding the second part of your question, I have found combo boxes are a valuable way to have users input data. I almost always base the CB's on a table to enable simple viewing and updating of data. Once this is done I make a simple data entry form for the table. I then create a command button on the form that holds the CB. This button opens the data entry form to the current value, if there is a current value (for editing). The command button opens the data entry form to a new record if there is no value selected in the CB (for new record entry).
IN this way I can add a New Supplier to a Invoice record, or look up information about an existing Supplier without leaving the Invoice form....
HTH
Chris

Hello Chris,

I only want the user to select a supplier from the cb once, if there try to choose a different supplier without creating a new record, I need a dialog box to tel them this can't be done, but give them a choice to create a new record. I'm too far on with the form to be making any big changes.

Thanks for your reply.
TAC