diff --git a/src/viewer.js b/src/viewer.js
index a87c52e9..b6026148 100644
--- a/src/viewer.js
+++ b/src/viewer.js
@@ -1014,7 +1014,7 @@ function openTileSource( viewer, source ) {
         });
     }
     
-    if( _this.preserveVewport ){
+    if( _this.preserveViewport ){
         _this.viewport.resetContentSize( _this.source.dimensions );
     }