PRB: Toolbar Buttons Not Updated/Painted Correctly in Windows 95

• The Microsoft Foundation Classes (MFC) included with:

      - Microsoft Visual C++, 32-bit Editions, versions 4.0, 4.1, 4.2,
        4.2b, 5.0
  

SYMPTOMS

Buttons on a toolbar that were created using CToolBar may not update or paint correctly if the buttons have text associated with them. This happens only on Windows 95 machines with Internet Explorer 3.x installed.

CAUSE

This is due to a bug in the ComCtl32.dll (version 4.70) that is installed with Internet Explorer 3.x.

RESOLUTION

To work around this problem, derive a class from CToolBar and override DefWindowProc as follows:

   // MyToolBar.h : headerfile
   class CMyToolBar : public CToolBar
   {
   ...
   protected:
      virtual LRESULT DefWindowProc(UINT message, WPARAM wParam,
         LPARAM lParam);
   ...
   };


   // MyToolBar.cpp : implementation file
   #include "stdafx.h"
   #include "mytoolbar.h"
   ...
   LRESULT CMyToolBar::DefWindowProc(UINT message, WPARAM wParam,
      LPARAM lParam)
   {
      // the toolbar common control does not handle these messages well
      // if the WS_VISIBLE style is not turned on under Windows 95
      DWORD style = GetStyle();
      if (message == TB_DELETEBUTTON || message == TB_INSERTBUTTON)
      {
         if (!(style & WS_VISIBLE))
         {
            ModifyStyle(0,WS_VISIBLE);
         }
      }
      LRESULT lresult = CToolBar::DefWindowProc(message, wParam, lParam);
      if (message == TB_DELETEBUTTON || message ==TB_INSERTBUTTON)
      {
         if (!(style & WS_VISIBLE))
         {
            ModifyStyle(WS_VISIBLE,0);
         }
      }
      return lresult;
   }

STATUS

Microsoft is researching this problem and will post new information here in the Microsoft Knowledge Base as it becomes available.

MORE INFORMATION

Steps to Reproduce Behavior

Add the following code to CMainFrame::OnCreate in a Default Appwizard Application:

   BOOL CMainFrame::OnCreate(...)
   {
      ...
      m_wndToolBar.SetButtonText(0,"New");
      m_wndToolBar.SetButtonText(1,"Open");
      m_wndToolBar.SetButtonText(2,"Save");
      m_wndToolBar.SetButtonText(4,"Cut");
      m_wndToolBar.SetButtonText(5,"Copy");
      m_wndToolBar.SetButtonText(6,"Paste");
      m_wndToolBar.SetButtonText(8,"Print");
      m_wndToolBar.SetButtonText(9,"About");

      CRect temp;
      m_wndToolBar.GetItemRect(0,&temp);
      m_wndToolBar.SetSizes( CSize(temp.Width(),temp.Height()),
         CSize(16,15));

      return 0;

   }