Of course there is, in your click event you can test for the value using a dCount (or the return value of the dLookup):
Code:
If dCount("*"," tblJobTitle","JobTitle='" & Forms!frmWithTextBox!JobTitle & "'")=0 Then
If Msgbox("The select job title does not yet exist in the Job Titels table. Do you want to add it?",vbquestion +vbYesNo,"Add newjob title")=vbNo then Exit Sub 'skip updating the combo
'if you got here the user wants to add it
'open a modal\dialog form bount to the tblJobTitles in DataAdd mode and pass it the new value directly or as the OpenArgs
docmd.OpenForm "popAddJobTitle",acNormal,,,acFormAdd,acDialog,Me.JobTitle 'using OpenArgs - in the Load event of the modal form add Me.JobTitle=Me.OpenArgs
Forms!popAddJobTitle!JobTitle=Me.JobTitle ' directly into the now open form - ;this line needs the previous one but without the OpenArgs
End If
'now that the modal form is closed and the new value added to the table go ahead and update the combo
Forms!frmWithCombo!JobTitle=dLookup("JobTitleID"," tblJobTitle","JobTitle='" & Me.JobTitle & "'")
Cheers,