diff --git a/addon/bootstrap.js b/addon/bootstrap.js
index 1613869..1b50280 100644
--- a/addon/bootstrap.js
+++ b/addon/bootstrap.js
@@ -54,7 +54,6 @@ function shutdown({ id, version, resourceURI, rootURI }, reason) {
   if (reason === APP_SHUTDOWN) {
     return;
   }
-  Services.wm.removeListener(windowListener);
 
   if (typeof Zotero === "undefined") {
     Zotero = Components.classes["@zotero.org/Zotero;1"].getService(
diff --git a/src/hooks.ts b/src/hooks.ts
index 998c878..7b4efa2 100644
--- a/src/hooks.ts
+++ b/src/hooks.ts
@@ -27,8 +27,7 @@ async function onStartup() {
 
 async function onMainWindowLoad(win: Window): Promise<void> {
   // Create ztoolkit for every window
-  const _ztoolkit = createZToolkit();
-  addon.data.ztoolkit = _ztoolkit;
+  addon.data.ztoolkit = createZToolkit();
 
   const popupWin = new ztoolkit.ProgressWindow(config.addonName, {
     closeOnClick: true,