Private Declare Function SetWindowPos Lib "user32" _
  Alias "SetWindowPos" (ByVal hwnd As Long, _
  ByVal hWndInsertAfter As Long, ByVal x As Long, _
  ByVal y As Long, ByVal cx As Long, _
  ByVal cy As Long, ByVal wFlags As Long) As Long
 
Private Const HWND_TOPMOST = -1
Private Const HWND_NOTOPMOST = -2
Private Const SWP_NOMOVE = &H2
Private Const SWP_NOSIZE = &H1
 
' Fenster in den Vordergrund setzen
Public Sub FormOnTop(ByVal hWnd As Long, _
  ByVal OnTop As Boolean)
 
  If OnTop Then
    ' immer im Vordergrund
    SetWindowPos hwnd, HWND_TOPMOST, 0, 0, 0, 0, _
      SWP_NOMOVE Or SWP_NOSIZE
  Else
    ' normal
    SetWindowPos hwnd, HWND_NOTOPMOST, 0, 0, 0, 0, _
      SWP_NOMOVE Or SWP_NOSIZE
  End If
End Sub