--- a/layout/base/nsCSSFrameConstructor.cpp
+++ b/layout/base/nsCSSFrameConstructor.cpp
@@ -2160,17 +2160,21 @@ nsCSSFrameConstructor::ConstructTableCel
 
   return NS_OK;
 }
 
 static PRBool 
 NeedFrameFor(nsIFrame*   aParentFrame,
              nsIContent* aChildContent) 
 {
-  NS_PRECONDITION(!aChildContent->GetPrimaryFrame(), "Why did we get called?");
+  // XXX the GetContent() != aChildContent check is needed due to bug 135040.
+  // Remove it once that's fixed.
+  NS_PRECONDITION(!aChildContent->GetPrimaryFrame() ||
+                  aChildContent->GetPrimaryFrame()->GetContent() != aChildContent,
+                  "Why did we get called?");
 
   // don't create a whitespace frame if aParentFrame doesn't want it.
   // always create frames for children in generated content. counter(),
   // quotes, and attr() content can easily change dynamically and we don't
   // want to be reconstructing frames. It's not even clear that these
   // should be considered ignorable just because they evaluate to
   // whitespace.