BUG: Edit Controls and WS_CLIPCHILDREN Function Differently

ID: Q111652

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 kbGrpUser kbWinOS310bug
Version : WINDOWS:3.1
Platform : WINDOWS
Issue type : kbbug