(svn r22618) -Fix [FS#4653]: When changing difficulty settings over the network, do not just reopen the difficulty window if any game options window is opened; instead invalidate them properly.

src/window_type.h

@@ -123,6 +123,7 @@ enum GameOptionsInvalidationData {
 	GOID_NEWGRF_RESCANNED,     ///< NewGRFs were just rescanned.
 	GOID_NEWGRF_LIST_EDITED,   ///< List of active NewGRFs is being edited.
 	GOID_NEWGRF_PRESET_LOADED, ///< A NewGRF preset was picked.
+	GOID_DIFFICULTY_CHANGED,   ///< Difficulty settings were changed.
 };
 
 struct Window;