diff --git a/src/window_gui.h b/src/window_gui.h
--- a/src/window_gui.h
+++ b/src/window_gui.h
@@ -678,7 +678,7 @@ public:
 	/**
 	 * Called once per (game) tick.
 	 */
-	virtual void OnTick() {}
+	virtual void OnGameTick() {}
 
 	/**
 	 * Called once every 100 (game) ticks.
@@ -686,6 +686,11 @@ public:
 	virtual void OnHundredthTick() {}
 
 	/**
+	 * Called periodically.
+	 */
+	virtual void OnRealtimeTick(uint delta_ms) {}
+
+	/**
 	 * Called when this window's timeout has been reached.
 	 */
 	virtual void OnTimeout() {}