diff --git a/mozilla/layout/mathml/base/src/nsMathMLContainerFrame.h b/mozilla/layout/mathml/base/src/nsMathMLContainerFrame.h
index 944db75b529..f087867109a 100644
--- a/mozilla/layout/mathml/base/src/nsMathMLContainerFrame.h
+++ b/mozilla/layout/mathml/base/src/nsMathMLContainerFrame.h
@@ -479,9 +479,6 @@ public:
   }
 
   virtual PRBool IsFrameOfType(PRUint32 aFlags) const {
-    // Override nsInlineFrame.   XXX Should we really?
-    if (aFlags & (nsIFrame::eBidiInlineContainer))
-      return PR_FALSE;
     return nsInlineFrame::IsFrameOfType(aFlags & ~(nsIFrame::eMathML));
   }