diff --git a/index.html b/index.html
index 673617a..d02480e 100644
--- a/index.html
+++ b/index.html
@@ -175,7 +175,7 @@
         cursor: pointer;
         display: inline-block;
       }
-      .call_el .expand_icon {
+      .call_el .expand_icon, .call_el .expand_icon_placeholder {
         padding-left: 5px;
         padding-right: 2px;
       }
diff --git a/src/editor/calltree.js b/src/editor/calltree.js
index 6917ff7..d75490d 100644
--- a/src/editor/calltree.js
+++ b/src/editor/calltree.js
@@ -87,7 +87,7 @@ export class CallTree {
         click: e => this.on_click_node(e, n.id),
       },
         !is_expandable(n)
-          ? '\xa0'
+          ? el('span', 'expand_icon_placeholder', '\xa0')
           : el('span', 'expand_icon', is_expanded ? '▼' : '▶'),
         n.toplevel
         ? el('span', '',