diff -u b/core/misc/matchmedia.js b/core/misc/matchmedia.js
--- b/core/misc/matchmedia.js
+++ b/core/misc/matchmedia.js
@@ -72,10 +72,8 @@
     addListener: function (callback) {
       var handler = (function (mql, debounced) {
         return function () {
-          var self = mql;
-          var cb = debounced;
-          self.check();
-          cb.call(self, self);
+          mql.check();
+          debounced.call(mql, mql);
         };
       }(this, debounce(callback, 250)));
       this.listeners.push({