code: function() {
  			if (!this.settings.placeholder) return;
  			var $input = this.$control_input;
  	
  			if (this.items.length) {
  				$input.removeAttr('placeholder');
  			} else {
  				$input.attr('placeholder', this.settings.placeholder);
  			}
  			$input.triggerHandler('update', {force: true});
  		}
docs: Shows/hide the input placeholder depending
  on if there items in the list already.