Bug 1226185 - Ensure to unmount about:debugging components on tab close. r=janx

devtools/client/aboutdebugging/aboutdebugging.js

@@ -107,6 +107,9 @@ var AboutDebugging = {
       Services.prefs.removeObserver(pref, listener);
     });
     this._prefListeners = [];
+
+    React.unmountComponentAtNode(document.querySelector("#addons"));
+    React.unmountComponentAtNode(document.querySelector("#workers"));
   },
 };