diff --git a/src/genworld_gui.cpp b/src/genworld_gui.cpp
--- a/src/genworld_gui.cpp
+++ b/src/genworld_gui.cpp
@@ -425,8 +425,14 @@ struct GenerateLandscapeWindow : public 
 		}
 	}
 
-	virtual void OnInvalidateData(int data = 0)
+	/**
+	 * Some data on this window has become invalid.
+	 * @param data Information about the changed data.
+	 * @param gui_scope Whether the call is done from GUI scope. You may not do everything when not in GUI scope. See #InvalidateWindowData() for details.
+	 */
+	virtual void OnInvalidateData(int data = 0, bool gui_scope = true)
 	{
+		if (!gui_scope) return;
 		/* Update the climate buttons */
 		this->SetWidgetLoweredState(GLAND_TEMPERATE, _settings_newgame.game_creation.landscape == LT_TEMPERATE);
 		this->SetWidgetLoweredState(GLAND_ARCTIC,    _settings_newgame.game_creation.landscape == LT_ARCTIC);