' === Fenster exakt mittig auf Monitor der Referenzform setzen ===
Public Sub CenterFormOnSameMonitor(ByVal frmToCenter As Form, ByVal _
  referenceForm As Form)
    Dim hMonitor As Long
    Dim mi As MONITORINFO
    Dim hwndTarget As Long
 
    hMonitor = MonitorFromWindow(referenceForm.hWnd, MONITOR_DEFAULTTONEAREST)
    mi.cbSize = Len(mi)
 
    If GetMonitorInfo(hMonitor, mi) <> 0 Then
        Dim monitorLeft As Long
        Dim monitorTop As Long
        Dim monitorWidth As Long
        Dim monitorHeight As Long
        Dim winWidth As Long
        Dim winHeight As Long
        Dim newLeft As Long
        Dim newTop As Long
 
        ' Monitor-Infos holen (in echten Pixeln)
        monitorLeft = mi.rcWork.Left
        monitorTop = mi.rcWork.Top
        monitorWidth = mi.rcWork.Right - mi.rcWork.Left
        monitorHeight = mi.rcWork.Bottom - mi.rcWork.Top
 
        ' Fenstergröße (in Pixeln!)
        winWidth = frmToCenter.Width \ Screen.TwipsPerPixelX
        winHeight = frmToCenter.Height \ Screen.TwipsPerPixelY
 
        ' Neue Position berechnen (zentriert im Arbeitsbereich des Monitors)
        newLeft = monitorLeft + ((monitorWidth - winWidth) \ 2)
        newTop = monitorTop + ((monitorHeight - winHeight) \ 2)
 
        ' Fensterposition setzen (in Pixeln!)
        hwndTarget = frmToCenter.hWnd
        Call SetWindowPos(hwndTarget, 0, newLeft, newTop, 0, 0, SWP_NOSIZE Or _
          SWP_NOZORDER Or SWP_NOACTIVATE)
    End If
End Sub
' === Form relativ zur Referenzform positionieren ===
Public Sub PositionFormRelativeToForm(ByVal frmToMove As Form, ByVal _
  referenceForm As Form, ByVal position As String, Optional ByVal spacing As _
  Long = 10)
    Dim refLeft As Long
    Dim refTop As Long
    Dim refWidth As Long
    Dim refHeight As Long
    Dim winWidth As Long
    Dim winHeight As Long
    Dim newLeft As Long
    Dim newTop As Long
 
    ' Konvertiere Referenz-Form-Koordinaten in Pixel
    refLeft = referenceForm.Left \ Screen.TwipsPerPixelX
    refTop = referenceForm.Top \ Screen.TwipsPerPixelY
    refWidth = referenceForm.Width \ Screen.TwipsPerPixelX
    refHeight = referenceForm.Height \ Screen.TwipsPerPixelY
 
    ' Ziel-Form-Größe in Pixel
    winWidth = frmToMove.Width \ Screen.TwipsPerPixelX
    winHeight = frmToMove.Height \ Screen.TwipsPerPixelY
 
    Select Case LCase(position)
        Case "right"
            newLeft = refLeft + refWidth + spacing
            newTop = refTop + (refHeight - winHeight) \ 2
 
        Case "left"
            newLeft = refLeft - winWidth - spacing
            newTop = refTop + (refHeight - winHeight) \ 2
 
        Case "below"
            newLeft = refLeft + (refWidth - winWidth) \ 2
            newTop = refTop + refHeight + spacing
 
        Case "above"
            newLeft = refLeft + (refWidth - winWidth) \ 2
            newTop = refTop - winHeight - spacing
 
        Case "center"
            newLeft = refLeft + (refWidth - winWidth) \ 2
            newTop = refTop + (refHeight - winHeight) \ 2
 
        Case Else
            ' Default: center
            newLeft = refLeft + (refWidth - winWidth) \ 2
            newTop = refTop + (refHeight - winHeight) \ 2
    End Select
 
    ' Position mit SetWindowPos setzen (in echten Pixeln)
    Call SetWindowPos(frmToMove.hWnd, 0, newLeft, newTop, 0, 0, SWP_NOSIZE Or _
      SWP_NOZORDER Or SWP_NOACTIVATE)
End Sub