微软没有发现的VB与VBA的BUG——关于窗体子类化

很多人认为理论上VB与VBA没有区别，可是事实真的如此吗？

 因为程序需要，我用WORD在VBA中插入了一个用户窗体USERFORM1，并且将该窗体子类化了。

  但是程序运行后，窗体的标题栏似乎是一个“禁区”，无论在标题栏鼠标左击、右击，或者左击窗体右上角的关闭按钮，都会导致程序停止响应，包括WORD，可是在VB环境中却不会出现这种现象……

 我实在就迷茫了，不知道为什么，怎么解决？

  跪求各位大神不吝赐教啊~！！~！


  相关代码如下：
  '在USERFORM1中
  Private Sub UserForm_Click()
  Unload UserForm1
  End Sub

  Private Sub UserForm_Initialize()
      FrmHwnd = FindWindow(vbNullString, UserForm1.Caption)
      lpPrevWndProc = SetWindowLong(FrmHwnd, GWL_WNDPROC, AddressOf WindowProcTest)

  End Sub

  Private Sub UserForm_QueryClose(Cancel As Integer, CloseMode As Integer)
      SetWindowLong FrmHwnd, GWL_WNDPROC, lpPrevWndProc
  End Sub

  '在模块中
  Public Const GWL_WNDPROC = -4

  Public lpPrevWndProc   As Long

  Public FrmHwnd 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 FindWindow Lib "user32" Alias "FindWindowA" (ByVal lpClassName As String, ByVal lpWindowName As String) 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 Function WindowProcTest(ByVal hwnd As Long, _
                             ByVal uMsg As Long, _
                             ByVal wParam As Long, _
                             ByVal lParam As Long) As Long


      WindowProcTest = CallWindowProc(lpPrevWndProc, hwnd, uMsg, wParam, lParam)

  End