diff --git a/dom/base/nsGlobalWindow.cpp b/dom/base/nsGlobalWindow.cpp
index 090a2d486beb..dc8ecce90f63 100644
--- a/dom/base/nsGlobalWindow.cpp
+++ b/dom/base/nsGlobalWindow.cpp
@@ -194,6 +194,7 @@
 
 #include "mozilla/dom/SelectionChangeEvent.h"
 
+#include "mozilla/AddonPathService.h"
 #include "mozilla/Services.h"
 #include "mozilla/Telemetry.h"
 #include "nsLocation.h"
@@ -2264,6 +2265,7 @@ CreateNativeGlobalForInner(JSContext* aCx,
     top = aNewInner->GetTop();
   }
   JS::CompartmentOptions options;
+  options.setAddonId(MapURIToAddonID(aURI));
   if (top) {
     if (top->GetGlobalJSObject()) {
       options.setSameZoneAs(top->GetGlobalJSObject());
diff --git a/js/xpconnect/src/XPCWrappedNativeScope.cpp b/js/xpconnect/src/XPCWrappedNativeScope.cpp
index 35eedabb6415..fcbf337c9e98 100644
--- a/js/xpconnect/src/XPCWrappedNativeScope.cpp
+++ b/js/xpconnect/src/XPCWrappedNativeScope.cpp
@@ -346,6 +346,11 @@ XPCWrappedNativeScope::EnsureAddonScope(JSContext *cx, JSAddonId *addonId)
     MOZ_ASSERT(addonId);
     MOZ_ASSERT(nsContentUtils::IsSystemPrincipal(GetPrincipal()));
 
+    // If the global is already part of the add-on then there's no reason to
+    // create a new one.
+    if (AddonIdOfObject(global) == addonId)
+        return global;
+
     // If we already have an addon scope object, we know what to use.
     for (size_t i = 0; i < mAddonScopes.Length(); i++) {
         if (JS::AddonIdOfObject(js::UncheckedUnwrap(mAddonScopes[i])) == addonId)