BUG: ALT+Key Combination in Property Page Causes Stack Overflow

• The Microsoft Foundation Classes (MFC) included with: - Microsoft Visual C++, 32-bit Editions, version 5.0

SYMPTOMS

If you press an ALT+key combination (generating a WM_SYSCOMMAND) with keyboard focus on the property page for an MFC ActiveX control and the key does not correspond to a mnemonic on the page, you will get a stack overflow.

CAUSE

COlePropertyPage::WindowProc() traps the WM_SYSCOMMAND and calls IPropertyPageSite::TranslateAccelerator(). This function in turns sends the WM_SYSCOMMAND message back to the page. This results in a recursion until you run out of stack space.

RESOLUTION

 Override COlePropertyPage::WindowProc() and return TRUE if the message is

   LRESULT CMyPropPage::WindowProc(UINT msg, WPARAM wParam, LPARAM lParam)
   {
      //Return without processing if WM_SYSCOMMAND.
      if (WM_SYSCOMMAND == msg)
         return TRUE;
      else
         return COlePropertyPage::WindowProc(msg, wParam, lParam);
   }

STATUS

Microsoft has confirmed this to be a bug in the Microsoft products listed at the beginning of this article. We are researching this bug and will post new information here in the Microsoft Knowledge Base as it becomes available. (c) Microsoft Corporation 1997, All Rights Reserved. Contributions by Samson Tanrena, Microsoft Corporation

Keywords          : MfcOLE
Version           : WINNT:5.0
Platform          : winnt
Issue type        : kbbug