diff --git a/widget/src/xpwidgets/nsFileSpecWithUIImpl.cpp b/widget/src/xpwidgets/nsFileSpecWithUIImpl.cpp
index b48a23fc42b..85b64f32378 100644
--- a/widget/src/xpwidgets/nsFileSpecWithUIImpl.cpp
+++ b/widget/src/xpwidgets/nsFileSpecWithUIImpl.cpp
@@ -356,7 +356,7 @@ NS_IMETHODIMP nsFileSpecWithUIImpl::chooseDirectory(const char *title)
 } // nsFileSpecWithUIImpl::chooseDirectory
 
 //----------------------------------------------------------------------------------------
-nsresult NS_NewFileSpecWithUI(nsIFileSpecWithUI** result)
+NS_WIDGET nsresult NS_NewFileSpecWithUI(nsIFileSpecWithUI** result)
 //----------------------------------------------------------------------------------------
 {
 	if (!result)