[DevTools] Make Audits results tree non-collapsible.

third_party/WebKit/Source/devtools/front_end/audits/AuditsPanel.js

Index: third_party/WebKit/Source/devtools/front_end/audits/AuditsPanel.js
diff --git a/third_party/WebKit/Source/devtools/front_end/audits/AuditsPanel.js b/third_party/WebKit/Source/devtools/front_end/audits/AuditsPanel.js
index beb6fd8a3bc1e1350d004073e914653eaeb47a54..390d1a226d4b74b3d87e84488fb1533c08bc2c04 100644
--- a/third_party/WebKit/Source/devtools/front_end/audits/AuditsPanel.js
+++ b/third_party/WebKit/Source/devtools/front_end/audits/AuditsPanel.js
@@ -48,6 +48,7 @@ Audits.AuditsPanel = class extends UI.PanelWithSidebar {
     this._auditResultsTreeElement.selectable = false;
     this._auditResultsTreeElement.listItemElement.classList.add('audits-sidebar-results');
     this._auditResultsTreeElement.expand();
+    this._auditResultsTreeElement.setCollapsible(false);
     this._sidebarTree.appendChild(this._auditResultsTreeElement);
 
     this._constructCategories();