diff --git a/content/base/src/nsObjectLoadingContent.cpp b/content/base/src/nsObjectLoadingContent.cpp
index e55b166266b6..e3402d2299c4 100644
--- a/content/base/src/nsObjectLoadingContent.cpp
+++ b/content/base/src/nsObjectLoadingContent.cpp
@@ -2450,7 +2450,7 @@ nsObjectLoadingContent::UnloadObject(bool aResetState)
 
   mScriptRequested = false;
 
-  if (!mInstanceOwner) {
+  if (mIsStopping) {
     // The protochain is normally thrown out after a plugin stops, but if we
     // re-enter while stopping a plugin and try to load something new, we need
     // to throw away the old protochain in the nested unload.