diff --git a/webshell/src/nsWebWidget.cpp b/webshell/src/nsWebWidget.cpp
index f4e03ef3d66d..622cd519679d 100644
--- a/webshell/src/nsWebWidget.cpp
+++ b/webshell/src/nsWebWidget.cpp
@@ -441,7 +441,9 @@ NS_IMETHODIMP WebWidgetImpl::LoadURL(const nsString& aURLSpec)
   }
 
   // Now load the document
+  mPresShell->EnterReflowLock();
   doc->LoadURL(url);
+  mPresShell->ExitReflowLock();
 
   NS_RELEASE(doc);