ainer').each(function() {
                            $(this).children('.item').matchHeight('remove');
                        });
                    });

                    // button to show hidden elements
                    $('.btn-hidden').click(function() {
                        $('body').removeClass('test-hidden');
                    });

                    // example of update callbacks (uncomment to test)
                    $.fn.matchHeight._beforeUpdate = function(event, groups) {
         