code: function(e) {
  			this.iterate(false, false, e.shiftKey, true);
  			if(!this._ctrlKeyOn(e) && !e.shiftKey){
  				this.setSelection(this.currentModel(), false, true);
  			}
  			e.preventDefault();
  			return false;
  		}
docs: Up arrow key iterates the current row backward. If control key is on, browser's scroll up behavior takes over. If shift key is on, it toggles the check box and iterates backward.