Issue 2816 - Partial fix for EHH button in inspector tool, preview functionality still broken

chrome/content/frameScript.js

+/*
+ * This Source Code is subject to the terms of the Mozilla Public License
+ * version 2.0 (the "License"). You can obtain a copy of the License at
+ * http://mozilla.org/MPL/2.0/.
+ */
+
+(function()
+{
+  const Cu = Components.utils;
+
+  let rand = Components.stack.filename.replace(/.*\?/, "");
+  let module = "chrome://elemhidehelper/content/actor.jsm?" + rand;
+  let {shutdown} = Cu.import(module, {});
+
+  addMessageListener("ElemHideHelper:Shutdown", onShutdown);
+
+  function onShutdown()
+  {
+    shutdown();
+    Cu.unload(module);
+    removeMessageListener("ElemHideHelper:Shutdown", onShutdown);
+  }
+})();