DOCUMENT:Q161872  31-JUL-2001  [visualc]
TITLE   :FIX: ActiveX Control Fails to Fire Click Event
PRODUCT :Microsoft C Compiler
PROD/VER:4.20
OPER/SYS:
KEYWORDS:kbVC kbBug kbfix kbISSkbbuglist kbfixlist

======================================================================
-------------------------------------------------------------------------------
The information in this article applies to:

 - Microsoft Visual C++, 32-bit Enterprise Edition, version 4.2 
 - Microsoft Visual C++, 32-bit Professional Edition, version 4.2 
-------------------------------------------------------------------------------

SYMPTOMS
========

If you create an ActiveX control that subclasses a button, you may find that the
control doesn't fire a "click" event. You can observe this behavior by running
the BUTTON sample included with Visual C++ 4.2.

CAUSE
=====

There is a bug in the COleControl::OnLButtonUp() function. CWnd::OnLButtonUp()
should be called within the function before calling COleControl::ButtonUp().

RESOLUTION
==========

You can work around the problem by trapping the WM_LBUTTONUP message in your
control. Copy the code from the OnLButtonUp() function located in
\MSDEV\MFC\SRC\CTLEVENT.CPP and place it into your new handler. Move the call to
CWnd::OnLButtonUp() before the call to ButtonUp() so that the new function looks
like the following:

      void CYourButtonCtrl::OnLButtonUp(UINT nFlags, CPoint point)
      {
         HWND hWndSave = m_hWnd;
         CWnd::OnLButtonUp(nFlags, point);  // moved the call here

              ButtonUp(LEFT_BUTTON, nFlags, point);
         if (m_hWnd != hWndSave)
            return;

         if (m_bInPlaceActive && !m_bUIActive && m_bPendingUIActivation &&
            (GetFocus() == this || IsChild(GetFocus())))
         {
            m_bPendingUIActivation = FALSE;
            OnActivateInPlace(TRUE, NULL);
         }
      }

STATUS
======

Microsoft has confirmed this to be a bug in the Microsoft products listed at the
beginning of this article. This bug was corrected in Visual C++ version 4.2b.

REFERENCES
==========

For more information about Visual C++ 4.2b, please see the following article in
the Microsoft Knowledge Base:

   Q156934 PATCH: Visual C++ 4.2b Patch

Additional query words: 4.20 kbdsd FIXLIST4.20b

======================================================================
Keywords          : kbVC kbBug kbfix kbISS kbbuglist kbfixlist
Technology        : kbVCsearch kbAudDeveloper kbVC420 kbVC32bitSearch
Version           : 4.20
Solution Type     : kbfix

=============================================================================

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