Merge branch 'develop' of https://github.com/almende/vis into develop

docs/index.html

@@ -23,7 +23,9 @@
 
   <p>
     The library is developed by
-    <a href="http://almende.com" target="_blank">Almende B.V.</a>
+    <a href="http://almende.com" target="_blank">Almende B.V.</a>.
+    Vis.js runs fine on Chrome, Firefox, Opera, Safari, IE9+, and most mobile
+    browsers (with full touch support).
   </p>
 
   <h2 id="Components">Components</h2>

src/graph/Graph.js

@@ -737,7 +737,6 @@ Graph.prototype._create = function () {
   this.frame.className = 'graph-frame';
   this.frame.style.position = 'relative';
   this.frame.style.overflow = 'hidden';
-  this.frame.style.zIndex = "1";
 
   // create the graph canvas (HTML canvas element)
   this.frame.canvas = document.createElement( 'canvas' );