It is possible to receive a WM_PAINT message in Windows without there being an update region. For example, this can be caused by someone calling RedrawWindow() with the RDW_INTERNALPAINT flag set. In this case, GetUpdateRect() will indicate that there is no update region and calling BeginPaint()/EndPaint() results in incorrect behavior. The credentials window in Network Identity Manager needs to perform special handling for this case by obtaining a proper device context and completing the drawing operation. Commit By: jaltman Revision: 19859 Changed Files: U trunk/src/windows/identity/ui/credwnd.c