diff --git a/src/views/treetable/TreeTableColResizeDemo.vue b/src/views/treetable/TreeTableColResizeDemo.vue
index 8b54658ac..3ce4a6984 100755
--- a/src/views/treetable/TreeTableColResizeDemo.vue
+++ b/src/views/treetable/TreeTableColResizeDemo.vue
@@ -11,7 +11,7 @@
         <div class="content-section implementation">
             <div class="card">
                 <h5>Fit Mode</h5>
-                <TreeTable :value="nodes" :resizableColumns="true" columnResizeMode="fit">
+                <TreeTable :value="nodes" :resizableColumns="true" columnResizeMode="fit" class="p-treetable-gridlines">
                     <Column field="name" header="Name" :expander="true"></Column>
                     <Column field="size" header="Size"></Column>
                     <Column field="type" header="Type"></Column>
@@ -20,7 +20,7 @@
 
             <div class="card">
                 <h5>Expand Mode</h5>
-                <TreeTable :value="nodes" :resizableColumns="true" columnResizeMode="expand">
+                <TreeTable :value="nodes" :resizableColumns="true" columnResizeMode="expand" class="p-treetable-gridlines">
                     <Column field="name" header="Name" :expander="true"></Column>
                     <Column field="size" header="Size"></Column>
                     <Column field="type" header="Type"></Column>