Public Function HookProc(ByVal nCode As Long, ByVal wParam As Long, _
                          Inf As CWPSTRUCT) As Long
    Dim R As RECT
    Static LastParam As Long
 
    If Inf.hWnd = mdi.hWnd Then
        If Inf.Message = WM_NCPAINT Or Inf.Message = WM_MOVE Then
            Call GetWindowRect(mdi.hWnd, R)
            Call SetWindowPos(Form1.infobutton.hWnd, 0, R.Right - (75 * _
              faktor), _
                          R.Top + 5.4, (16 * faktor), (14.5 * faktor), _
                          SWP_FRAMECHANGED)
        End If
    End If
End Function

'Setzt einen zusätzlichen Button
Public Sub SetTitleBarButton(Frm As Form, Button As CommandButton)
   Set varForm = Frm
   Set varButton = Button
 
   WHook = SetWindowsHookEx(4, AddressOf HookProc, 0, App.ThreadID)
   Call SetWindowLong(Form1.infobutton.hWnd, GWL_EXSTYLE, &H80)
   Call SetParent(Form1.infobutton.hWnd, GetParent(mdi.hWnd))
End Sub

'Entfernt den zusätzlichen Button
Public Sub Terminate()
    Call UnhookWindowsHookEx(WHook)
    Call SetParent(Form1.infobutton.hWnd, mdi.hWnd)
End Sub