BeginPaint/IntBeginPaint doesn't clear flags causing drawing problems

When BeginPaint/IntBeginPaint gets called and the Window->state has the WNDS_SENDERASEBACKGROUND flag set, the flags WNDS_SENDERASEBACKGROUND and WNDS_ERASEBACKGROUND are cleared like they should be. But when/if the WM_ERASEBKGND gets sent and the application returns 0 from the function, both WNDS_SENDERASEBACKGROUND and WNDS_ERASEBACKGROUND gets reset. This causes drawing problems for RedrawWindow and InvalidateRect the next time those funtions are called because WNDS_SENDERASEBACKGROUND has already been set. This could lead to unwanted WM_ERASEBKGND messages being sent, especially if those function don't want them.