KnowledgeBase Archive

An Archive of Early Microsoft KnowledgeBase Articles

View on GitHub

Q111652: BUG: Edit Controls and WS_CLIPCHILDREN Function Differently

Article: Q111652
Product(s): Microsoft Windows Software Development Kit
Version(s): WINDOWS:3.1
Operating System(s): 
Keyword(s): kb16bitonly kbEditCtrl kbGrpDSUser kbOSWin310bug
Last Modified: 12-NOV-1999

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

- Microsoft Windows Software Development Kit (SDK) 3.1 
-------------------------------------------------------------------------------

SYMPTOMS
========

Unnecessary painting is done when an edit control window is created with the
WS_CLIPCHILDREN style bit set.

CAUSE
=====

If an edit control window is created with the WS_CLIPCHILDREN style bit set, a
WM_PAINT message will be sent to the parent. In Windows version 3.0, the
rcUpdate is (0,0,0,0), which makes it very easy to ignore this WM_PAINT message.
In Windows version 3.1, the rcUpdate is the size of the child edit control,
which causes extra painting to be done. The WM_PAINT message is not necessary
because the child control itself does the painting, not the parent.

STATUS
======

Microsoft has confirmed this to be a bug in Windows version 3.1.

Additional query words:

======================================================================
Keywords          : kb16bitonly kbEditCtrl kbGrpDSUser kbOSWin310bug 
Technology        : kbAudDeveloper kbWin3xSearch kbSDKSearch kbWinSDKSearch kbWinSDK310
Version           : WINDOWS:3.1
Issue type        : kbbug

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

THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. MICROSOFT DISCLAIMS ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL, CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. SOME STATES DO NOT ALLOW THE EXCLUSION OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES SO THE FOREGOING LIMITATION MAY NOT APPLY.