server: Store a separate flag for windows that need to be erased in WM_PAINT.
This avoids the need to invalidate the window after WM_ERASEBKGND.
diff --git a/server/protocol.def b/server/protocol.def
index 6e13cb2..aaf6c2e 100644
--- a/server/protocol.def
+++ b/server/protocol.def
@@ -2256,6 +2256,7 @@
#define UPDATE_ALLCHILDREN 0x10 /* force repaint of all children */
#define UPDATE_NOCHILDREN 0x20 /* don't try to repaint any children */
#define UPDATE_NOREGION 0x40 /* don't return a region, only the flags */
+#define UPDATE_DELAYED_ERASE 0x80 /* still needs erase after BeginPaint */
/* Update the z order of a window so that a given rectangle is fully visible */
