Fix z-index issue in the profiler

front/src/css/timeline.css

@@ -224,7 +224,7 @@
   background: #EBD8E2;
   line-height: 1.3em;
   height: 1.3em;
-  z-index: 1;
+  z-index: 2;
 }
 .table .showingDetails .child span:hover {
   background: inherit;

front/src/less/timeline.less

@@ -257,7 +257,7 @@
             background: #EBD8E2;
             line-height: 1.3em;
             height: 1.3em;
-            z-index: 1;
+            z-index: 2;
         }
     }
 }