Private Sub ZoomControls(ByVal f As Control, fo As Drawing.Font, _
        factorwidth As Double, factorheight As Double)
 
   For Each ctl As Control In f.Controls
        ZoomControls(ctl, fo, factorwidth, factorheight)
 
        If TypeOf ctl Is ListBox Then
           'Listbox reagiert sonst nicht richtig ???
           Dim lb As ListBox = CType(ctl, ListBox)
           lb.Height = CInt(lb.Height * factorheight)
        Else
           ctl.Height = CInt(ctl.Height * factorheight)
        End If
        ctl.Font = fo
        ctl.Top = CInt(ctl.Top * factorheight)
        ctl.Width = CInt(ctl.Width * factorwidth)
        ctl.Left = CInt(ctl.Left * factorwidth)
   Next ctl
End Sub