This article was previously published under Q191756
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When a child window of the main window is created in a separate UI threadand the child window has the WS_SYSMENU style, when you switch to the childwindow's system menu by pressing the right arrow, the system stopsresponding and, eventually, after switching between other applications, thefollowing blue screen STOP message may occur:
For example, if an MDI child window is running on a separate thread and youselect a menu item, such as the File menu, and then press the right arrowkey, the frame or application's system menu will appear (that is, where youmove, size, minimize, maximize, and so on). If you press the right arrowkey again, the child window's system menu will appear. After you arrowdown, the menu items are not highlighted as expected. When you switch(press ALT+TAB) to another application, the system menu remains on top anddoes not redraw properly.
To resolve this problem, obtain the latest service pack for Windows NT 4.0 or Windows NT Server 4.0, Terminal Server Edition. For additional information, click the following article number to view the article in theMicrosoft Knowledge Base:
152734 How to Obtain the Latest Windows NT 4.0 Service Pack
Microsoft has confirmed that this is a problem in Windows NT 4.0 and Windows NT Server 4.0, Terminal Server Edition. This problem was first corrected in Windows NT 4.0 Service Pack 4.0 and Windows NT Server 4.0, Terminal Server Edition Service Pack 4.