diff --git a/src/_h5ai/client/css/inc/tree.less b/src/_h5ai/client/css/inc/tree.less
index 84a989aa..15eb2aae 100644
--- a/src/_h5ai/client/css/inc/tree.less
+++ b/src/_h5ai/client/css/inc/tree.less
@@ -7,7 +7,7 @@
     order: 1;
 
     padding: 16px 16px 16px 8px;
-    // border-right: 1px solid @col-border;
+    border-right: 1px solid @col-border;
     white-space: nowrap;
     max-width: 250px;
     overflow-x: hidden;