--- a/toolkit/components/reader/AboutReader.jsm
+++ b/toolkit/components/reader/AboutReader.jsm
@@ -36,16 +36,18 @@ var AboutReader = function(mm, win, arti
   this._mm = mm;
   this._mm.addMessageListener("Reader:CloseDropdown", this);
   this._mm.addMessageListener("Reader:AddButton", this);
   this._mm.addMessageListener("Reader:RemoveButton", this);
   this._mm.addMessageListener("Reader:GetStoredArticleData", this);
 
   this._docRef = Cu.getWeakReference(doc);
   this._winRef = Cu.getWeakReference(win);
+  this._innerWindowId = win.QueryInterface(Ci.nsIInterfaceRequestor)
+    .getInterface(Ci.nsIDOMWindowUtils).currentInnerWindowID;
 
   this._article = null;
 
   if (articlePromise) {
     this._articlePromise = articlePromise;
   }
 
   this._headerElementRef = Cu.getWeakReference(doc.getElementById("reader-header"));
@@ -55,20 +57,22 @@ var AboutReader = function(mm, win, arti
   this._contentElementRef = Cu.getWeakReference(doc.getElementById("moz-reader-content"));
   this._toolbarElementRef = Cu.getWeakReference(doc.getElementById("reader-toolbar"));
   this._messageElementRef = Cu.getWeakReference(doc.getElementById("reader-message"));
 
   this._scrollOffset = win.pageYOffset;
 
   doc.addEventListener("click", this, false);
 
-  win.addEventListener("unload", this, false);
+  win.addEventListener("pagehide", this, false);
   win.addEventListener("scroll", this, false);
   win.addEventListener("resize", this, false);
 
+  Services.obs.addObserver(this, "inner-window-destroyed", false);
+
   doc.addEventListener("visibilitychange", this, false);
 
   this._setupStyleDropdown();
   this._setupButton("close-button", this._onReaderClose.bind(this), "aboutReader.toolbar.close");
 
   const gIsFirefoxDesktop = Services.appinfo.ID == "{ec8030f7-c20a-464f-9b0e-13a3a9e97384}";
   if (gIsFirefoxDesktop) {
     // we're ready for any external setup, send a signal for that.
@@ -245,29 +249,42 @@ AboutReader.prototype = {
       case "devicelight":
         this._handleDeviceLight(aEvent.value);
         break;
 
       case "visibilitychange":
         this._handleVisibilityChange();
         break;
 
-      case "unload":
+      case "pagehide":
         // Close the Banners Font-dropdown, cleanup Android BackPressListener.
         this._closeDropdowns();
 
         this._mm.removeMessageListener("Reader:CloseDropdown", this);
         this._mm.removeMessageListener("Reader:AddButton", this);
         this._mm.removeMessageListener("Reader:RemoveButton", this);
         this._mm.removeMessageListener("Reader:GetStoredArticleData", this);
         this._windowUnloaded = true;
         break;
     }
   },
 
+  observe: function(subject, topic, data) {
+    if (subject.QueryInterface(Ci.nsISupportsPRUint64).data != this._innerWindowId) {
+      return;
+    }
+
+    Services.obs.removeObserver(this, "inner-window-destroyed", false);
+
+    this._mm.removeMessageListener("Reader:CloseDropdown", this);
+    this._mm.removeMessageListener("Reader:AddButton", this);
+    this._mm.removeMessageListener("Reader:RemoveButton", this);
+    this._windowUnloaded = true;
+  },
+
   _onReaderClose: function() {
     ReaderMode.leaveReaderMode(this._mm.docShell, this._win);
   },
 
   _setFontSize: function(newFontSize) {
     let containerClasses = this._doc.getElementById("container").classList;
 
     if (this._fontSize > 0)