--- a/src/gui.h	Mon May 05 11:24:58 2008 +0000
+++ b/src/gui.h	Mon May 05 11:36:43 2008 +0000
@@ -92,7 +92,7 @@
 void ShowErrorMessage(StringID msg_1, StringID msg_2, int x, int y);
 
 void ShowSmallMap();
-void ShowExtraViewPortWindow();
+void ShowExtraViewPortWindow(TileIndex tile = INVALID_TILE);
 void SetVScrollCount(Window *w, int num);
 void SetVScroll2Count(Window *w, int num);
 void SetHScrollCount(Window *w, int num);