all is ok, waitting to edit default theme

public/css/theme/default.css

@@ -1312,3 +1312,17 @@ background-position:-1px -670px
   overflow: scroll;
   list-style: none;
 }
+.notebook-setting {
+  display: none;
+  position: absolute;
+  right: 3px;
+  top: 0;
+  bottom: 0;
+  line-height: 30px;
+}
+.notebook-setting:before {
+  content: "\f013";
+}
+.ztree li a:hover .notebook-setting {
+  display: block;
+}