DOCUMENT:Q111652  12-NOV-1999  [win16sdk]
TITLE   :BUG: Edit Controls and WS_CLIPCHILDREN Function Differently
PRODUCT :Microsoft Windows Software Development Kit
PROD/VER:WINDOWS:3.1
OPER/SYS:
KEYWORDS:kb16bitonly kbEditCtrl kbGrpDSUser kbOSWin310bug

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The information in this article applies to:

 - Microsoft Windows Software Development Kit (SDK) 3.1 
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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:

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

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