Private Sub Form_Open(Cancel As Integer)
...

Call SubClassHookForm ' ставим хук

End Sub

Private Sub Form_Unload(Cancel As Integer)
...

Call SubClassUnHookForm ' снимаем хук
    If IsLoaded( "frmMonth" ) Then DoCmd.Close acForm,  "frmMonth" 

End Sub

'HOOK
Private Declare Function SetWindowLong Lib "user32" Alias "SetWindowLongA" (ByVal hwnd As Long, ByVal nIndex 

As Long, ByVal dwNewLong As Long) As Long

Private Const GWL_WNDPROC = (-4)
Private Const WM_LBUTTONUP = &H202 
Private Const WM_SETCURSOR = &H20
Private Declare Function CallWindowProc Lib "user32" Alias _
   "CallWindowProcA" (ByVal lpPrevWndFunc As Long, ByVal hwnd As Long, _
   ByVal msg As Long, ByVal wParam As Long, ByVal lParam As Long) As Long

Private m_PrevWndProc As Long

Public Sub SubClassHookForm()
' хук на Акес
   m_PrevWndProc = SetWindowLong(Access.hWndAccessApp, GWL_WNDPROC, AddressOf WindowProc)
End Sub

Public Sub SubClassUnHookForm()
On Error Resume Next
   Call SetWindowLong(Access.hWndAccessApp, GWL_WNDPROC, m_PrevWndProc)
End Sub

Private Function WindowProc(ByVal hwnd As Long, ByVal msg As Long, _
        ByVal wParam As Long, ByVal lParam As Long) As Long

    If msg = WM_SETCURSOR Then
        'выделяем старшую часть слова,
        'содержащую сообщение о том какая кнопка была нажата
        Select Case lParam \ &H10000
            Case WM_LBUTTONUP  ' Можно и другие кнопки
                If IsLoaded( "DatePicker" ) Then DoCmd.Close acForm,  "DatePicker" 
        End Select
    End If
    WindowProc = CallWindowProc(m_PrevWndProc, hwnd, msg, wParam, lParam)
End Function