code: function(aContexts, oModel) {
  			if (!aContexts.length) {
  				return;
  			}
  
  			var aItems = this._oControl.getItems(true);
  			for (var i = 0, c = 0, oItem; i < aItems.length; i++) {
  				oItem = aItems[i];
  
  				// group headers are not in binding context
  				if (!oItem.isGroupHeader()) {
  					oItem.setBindingContext(aContexts[c++], oModel);
  				}
  			}
  		}
docs: update context on all items except group headers