diff --git a/dom/base/nsGlobalWindow.cpp b/dom/base/nsGlobalWindow.cpp
index 66a8123be27..7a7030ec548 100644
--- a/dom/base/nsGlobalWindow.cpp
+++ b/dom/base/nsGlobalWindow.cpp
@@ -1404,8 +1404,9 @@ NS_IMPL_CYCLE_COLLECTING_RELEASE(nsGlobalWindow)
 
 
 NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN(nsGlobalWindow)
-  if (tmp->mDoc && nsCCUncollectableMarker::InGeneration(
-                     cb, tmp->mDoc->GetMarkedCCGeneration())) {
+  if ((tmp->mDoc && nsCCUncollectableMarker::InGeneration(
+                      cb, tmp->mDoc->GetMarkedCCGeneration())) ||
+      (nsCCUncollectableMarker::sGeneration && tmp->IsBlack())) {
     return NS_SUCCESS_INTERRUPTED_TRAVERSE;
   }