How did you create the event procedure? It won't work because the property does not have [Event Procedure] selected and ALLOCATION is not name of combobox, it is Combo32.
I never said to enter Dept manually. Select Allocation only. Dept can be displayed and/or saved by methods I described.
I recommend:
1. not to include ALLOCATION table in form Recordsource, just bind to Tbl_ALLOCATION-I
2. bind textbox to DEPT, not DEP
3. set combobox properties:
Name: cbxALLO
RowSource: SELECT ALLOCA, DEP FROM ALLOCATION ORDER BY [ALLOCA];
LimitToList: Yes
ColumnCount: 2
ColumnWidths: 1";0"
AfterUpdate event: [Event Procedure]
4. combobox AfterUpdate code
Private Sub cbxALLO_AfterUpdate()
Me!DEPT = Me.cbxALLO.Column(1)
End Sub