when should NOT we call the base class's corresponding function?

20041206:
when should NOT we call the base class's corresponding function?

void CDropDownBotton::OnKeyDown(UINT nChar, UINT nRepCnt, UINT nFlags) 
{
    // TODO: Add your message handler code here and/or call default
     if(nChar == VK_RETURN || nChar == VK_ESCAPE)
     {
          if (m_pOrigParent->IsDropDownDialogDown() )
          m_pOrigParent->OnDropdownButton();
  
     }
     //CButton::OnKeyDown(nChar, nRepCnt, nFlags);
}

in the code snippet above, the base class's corresponding function CButton::OnKeyDown(nChar, nRepCnt, nFlags); is comment out.

The reason is that the CButton has already been destroyed before we call CButton::OnKeyDown.

Another way to fix this kind of bug is to call CWnd::PostMeassage() instead of calling method to destroy CButton.