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Q161872: FIX: ActiveX Control Fails to Fire Click Event

Article: Q161872
Product(s): Microsoft C Compiler
Version(s): 4.20
Operating System(s): 
Keyword(s): kbVC kbBug kbfix kbISSkbbuglist kbfixlist
Last Modified: 31-JUL-2001

-------------------------------------------------------------------------------
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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