diff --git a/src/dock_gui.cpp b/src/dock_gui.cpp
--- a/src/dock_gui.cpp
+++ b/src/dock_gui.cpp
@@ -244,6 +244,7 @@ struct BuildDocksToolbarWindow : Window 
 		delete FindWindowById(WC_BUILD_STATION, 0);
 		delete FindWindowById(WC_BUILD_DEPOT, 0);
 		delete FindWindowById(WC_SELECT_STATION, 0);
+		delete FindWindowById(WC_BUILD_BRIDGE, 0);
 	}
 
 	virtual void OnPlacePresize(Point pt, TileIndex tile_from)