diff --git a/lib/ace/lib/useragent.js b/lib/ace/lib/useragent.js
index 14f0ee9b..b6989a8c 100644
--- a/lib/ace/lib/useragent.js
+++ b/lib/ace/lib/useragent.js
@@ -73,8 +73,9 @@ exports.isMac = (os == "mac");
 // Is the user using a browser that identifies itself as Linux
 exports.isLinux = (os == "linux");
 
+// Windows Store JavaScript apps (aka Metro apps written in HTML5 and JavaScript) do not use the "Microsoft Internet Explorer" string in their user agent, but "MSAppHost" instead.
 exports.isIE = 
-    navigator.appName == "Microsoft Internet Explorer"
+    (navigator.appName == "Microsoft Internet Explorer" || navigator.appName.indexOf("MSAppHost") >= 0)
     && parseFloat(navigator.userAgent.match(/MSIE ([0-9]+[\.0-9]+)/)[1]);
     
 exports.isOldIE = exports.isIE && exports.isIE < 9;