diff --git a/js/module/directed_graph.js b/js/module/directed_graph.js
index 5782cd85689be6ce3d85edbbf8c7f53aa21b2c17..42923fc30f60e4e2e32567ad1fa3d89125dc3ab2 100644
--- a/js/module/directed_graph.js
+++ b/js/module/directed_graph.js
@@ -111,7 +111,7 @@ DirectedGraphTracer.prototype = $.extend(true, Object.create(Tracer.prototype),
 
         var wgap = 1 / (maxDepth - 1);
         var dfs = function (node, depth, top, bottom) {
-            place(node, depth * wgap, (top + bottom) / 2);
+            place(node, top + bottom, depth * wgap);
             var children = 0;
             for (var i = 0; i < G[node].length; i++) {
                 if (G[node][i]) children++;
diff --git a/js/script.js b/js/script.js
index 0ca925380b1fab1c8d41370d1b97c998317f1664..28d4c09256b7200b3737b8893977bc65c9403728 100644
--- a/js/script.js
+++ b/js/script.js
@@ -239,11 +239,11 @@ $.getJSON('./algorithm/category.json', function (data) {
     for (var category in list) {
         (function (category) {
             var $category = $('<button class="category">')
-                .append('<i class="fa fa-fw fa-caret-down">')
+                .append('<i class="fa fa-fw fa-caret-right">')
                 .append(list[category].name);
             $category.click(function () {
                 $('[data-category="' + category + '"]').toggleClass('collapse');
-                $(this).find('i.fa').toggleClass('fa-caret-down fa-caret-right');
+                $(this).find('i.fa').toggleClass('fa-caret-right fa-caret-down');
             });
             $('#list').append($category);
             var subList = list[category].list;