おそらく、選択が行われるまで、コンボボックスの更新イベントをバイパスするフラグを立てることができます。
Private bLock as boolean ' declare at module level
' When a user clicks on the combobox
Private Sub DropDownArrow_Click() ' or cboComboBox_Click()
bLocked = True
End Sub
' This procedure is the one that does the updating from the data source.
' If the flag is set, do not touch the comboboxes.
Private Sub subUpdateComboBoxes()
If Not bLocked then
' Update the comboboxes
End If
End Sub
' When the selection is made, or the focus changes from the combobox.
' check if a selection is made and reset the flag.
Private Sub cboComboBox_AfterUpdate() ' Or LostFucus or something else
if Format(cboComboBox.Value) <> vbNullString Then
bLocked = False
End If
End Sub
それが役立つことを願っています。