[BUGFIX] Test property of the sidebar to set map position

lib/sidebar.js

@@ -21,12 +21,10 @@ define(function () {
     sidebar.appendChild(container);
 
     self.getWidth = function getWidth() {
-      if (sidebar.classList.contains('hidden')) {
+      if (sidebar.classList.contains('hidden') || button.offsetHeight === 0) {
         return 0;
       }
-
-      var small = window.matchMedia('(max-width: 630pt)');
-      return small.matches ? 0 : sidebar.offsetWidth;
+      return  sidebar.offsetWidth;
     };
 
     self.add = function add(d) {