--- a/browser/components/preferences/in-content/preferences.js
+++ b/browser/components/preferences/in-content/preferences.js
@@ -45,20 +45,17 @@ function register_module(categoryName, c
     inited: false,
     init() {
       categoryObject.init();
       this.inited = true;
     }
   });
 }
 
-addEventListener("DOMContentLoaded", function onLoad() {
-  removeEventListener("DOMContentLoaded", onLoad);
-  init_all();
-});
+document.addEventListener("DOMContentLoaded", init_all, {once: true});
 
 function init_all() {
   document.documentElement.instantApply = true;
 
   gSubDialog.init();
   register_module("paneGeneral", gMainPane);
   register_module("paneSearch", gSearchPane);
   register_module("panePrivacy", gPrivacyPane);

--- a/dom/base/nsDocument.cpp
+++ b/dom/base/nsDocument.cpp
@@ -7926,22 +7926,19 @@ nsDocument::GetEventTargetParent(EventCh
 
   aVisitor.mCanHandle = true;
    // FIXME! This is a hack to make middle mouse paste working also in Editor.
    // Bug 329119
   aVisitor.mForceContentDispatch = true;
 
   // Load events must not propagate to |window| object, see bug 335251.
   if (aVisitor.mEvent->mMessage != eLoad) {
-    nsPIDOMWindowInner* innerWindow = GetInnerWindow();
-    if (innerWindow && innerWindow->IsCurrentInnerWindow()) {
-      nsGlobalWindow* window = nsGlobalWindow::Cast(GetWindow());
-      aVisitor.mParentTarget =
-        window ? window->GetTargetForEventTargetChain() : nullptr;
-    }
+    nsGlobalWindow* window = nsGlobalWindow::Cast(GetWindow());
+    aVisitor.mParentTarget =
+      window ? window->GetTargetForEventTargetChain() : nullptr;
   }
   return NS_OK;
 }
 
 NS_IMETHODIMP
 nsDocument::CreateEvent(const nsAString& aEventType, nsIDOMEvent** aReturn)
 {
   NS_ENSURE_ARG_POINTER(aReturn);