Fix for bug # 103978. Problems with back/forward at cnn.com, mainly due to expired subframes and clicking back/forward fast. r=adamlock sr=rpotts

docshell/shistory/src/nsSHistory.cpp

@@ -531,7 +531,8 @@ NS_IMETHODIMP
 nsSHistory::UpdateIndex()
 {
   // Update the actual index with the right value. 
-  mIndex = mRequestedIndex;
+  if (mIndex != mRequestedIndex && mRequestedIndex != -1)
+    mIndex = mRequestedIndex;
   return NS_OK;
 }
 
@@ -706,6 +707,7 @@ nsSHistory::LoadEntry(PRInt32 aIndex, long aLoadType, PRUint32 aHistCmd)
 }
 
 
+
 PRBool
 nsSHistory::CompareSHEntry(nsISHEntry * aPrevEntry, nsISHEntry * aNextEntry, nsIDocShell * aParent,
 					nsIDocShell ** aDSResult, nsISHEntry ** aSHEResult)