Private Sub Form_Load()
  InitWndProc Me.hWnd
End Sub

Option Explicit

Public Declare Function GetProp Lib "user32" Alias "GetPropA" (ByVal hWnd As Long, ByVal lpString As String) As Long
Public Declare Function SetProp Lib "user32" Alias "SetPropA" (ByVal hWnd As Long, ByVal lpString As String, ByVal hData As Long) As Long
Public Declare Function SetWindowLong Lib "user32" Alias "SetWindowLongA" (ByVal hWnd As Long, ByVal nIndex As Long, ByVal dwNewLong As Long) As Long
Public Declare Function GetWindowLong Lib "user32" Alias "GetWindowLongA" (ByVal hWnd As Long, ByVal nIndex As Long) As Long
Public Declare Function CallWindowProc Lib "user32" Alias "CallWindowProcA" (ByVal lpPrevWndFunc As Long, ByVal hWnd As Long, ByVal Msg As Long, ByVal wParam As Long, ByVal lParam As Long) As Long

Public Const GWL_WNDPROC As Long = - 4 
Public Const WM_MOVE = &H3


Public Sub InitWndProc(hWnd As Long)

If GetProp(hWnd, "prevptr") =  0  Then
  SetProp hWnd, "prevptr", SetWindowLong(hWnd, GWL_WNDPROC, AddressOf FrmProc)
End If

End Sub
Public Function FrmProc(ByVal hw As Long, ByVal uMsg As Long, ByVal wParam As Long, ByVal lParam As Long) As Long

Dim lPrevWndProc As Long
lPrevWndProc = GetProp(hw, "prevptr")
If lPrevWndProc =  0  Then Exit Function

Select Case uMsg
  Case WM_MOVE
    Beep
End Select
FrmProc = CallWindowProc(lPrevWndProc, hw, uMsg, wParam, lParam)

End Function