diff --git a/web/map.js b/web/map.js
index be4d87d7..d41bd334 100644
--- a/web/map.js
+++ b/web/map.js
@@ -355,7 +355,7 @@ DynMap.prototype = {
 		};
 	},
 	unregisterTile: function(mapType, tileName) {
-		delete registeredTiles[tileName];
+		delete this.registeredTiles[tileName];
 	},
 	// TODO: Enable hash-links.
 /*	updateLink: function() {