Public Const WM_SYSCOMMAND = &H112
' einen Hook auf das Form erstellen
Public Sub CreateHook(ByVal lngHwnd As Long)
  lngPrevProc = SetWindowLong(lngHwnd, GWL_WNDPROC, AddressOf WindowProc)
End Sub
 
' WICHTIG: den Hook wieder freigeben
Public Sub ReleaseHook(ByVal lngHwnd As Long)
  SetWindowLong lngHwnd, GWL_WNDPROC, lngPrevProc
End Sub
 
' Subclassing
Public Function WindowProc(ByVal hwnd As Long, _
  ByVal uMsg As Long, _
  ByVal wParam As Long, _
  ByVal lParam As Long) As Long
 
  WindowProc = CallWindowProc(lngPrevProc, hwnd, uMsg, wParam, lParam)
 
  If uMsg = WM_SYSCOMMAND Then
    If wParam = intItemID Then
      MsgBox "Neuer Menüeintrag Click ... "
    End If
  End If
End Function