diff --git a/mozilla/docshell/base/nsDocShell.cpp b/mozilla/docshell/base/nsDocShell.cpp
index 02dc9891d50..5680ca9265a 100644
--- a/mozilla/docshell/base/nsDocShell.cpp
+++ b/mozilla/docshell/base/nsDocShell.cpp
@@ -4726,7 +4726,7 @@ nsDocShell::InternalLoad(nsIURI * aURI,
                          nsIRequest** aRequest)
 {
     nsresult rv = NS_OK;
-
+    
     // Initialize aDocShell/aRequest
     if (aDocShell) {
         *aDocShell = nsnull;
@@ -4735,6 +4735,15 @@ nsDocShell::InternalLoad(nsIURI * aURI,
         *aRequest = nsnull;
     }
 
+    // wyciwyg urls can only be loaded through history. Any normal load of
+    // wyciwyg through docshell is  illegal. Disallow such loads.
+    if (aURI && (aLoadType & LOAD_CMD_NORMAL)) {
+        PRBool isWyciwyg = PR_FALSE;
+        rv = aURI->SchemeIs("wyciwyg", &isWyciwyg);   
+        if ((isWyciwyg && NS_SUCCEEDED(rv)) || NS_FAILED(rv)) 
+            return NS_ERROR_FAILURE;
+    }
+
     //
     // First, notify any nsIContentPolicy listeners about the document load.
     // Only abort the load if a content policy listener explicitly vetos it!