code: function addChildAt(child, index) {
           if (index >= 0 && index < this.children.length) {
             if (child.ancestor instanceof me.Container) {
               child.ancestor.removeChildNow(child);
             } else {
               // only allocate a GUID if the object has no previous ancestor
               // (e.g. move one child from one container to another)
               if (child.isRenderable) {
                 // allocated a GUID value
                 child.GUID = me.utils.createGUID();
               }
             }
  
             child.ancestor = this;
             this.children.splice(index, 0, child);
  
             if (typeof child.onActivateEvent === "function" && this.isAttachedToRoot()) {
               child.onActivateEvent();
             }
  
             this.onChildChange.call(this, index);
             return child;
           } else {
             throw new Error("Index (" + index + ") Out Of Bounds for addChildAt()");
           }
         }
docs: Add a child to the container at the specified index<br>
  (the list won't be sorted after insertion)
  @name addChildAt
  @memberOf me.Container.prototype
  @function
  @param {me.Renderable} child
  @param {Number} index
  @return {me.Renderable} the added child