diff --git a/widget/src/xpwidgets/Makefile.in b/widget/src/xpwidgets/Makefile.in
index cfab44f3a924..95a492ce536d 100644
--- a/widget/src/xpwidgets/Makefile.in
+++ b/widget/src/xpwidgets/Makefile.in
@@ -37,6 +37,7 @@ CPPSRCS= \
 	nsBaseDragService.cpp    \
 	nsBaseClipboard.cpp      \
 	nsFileListTransferable.cpp \
+	nsFileSpecWithUIImpl.cpp \
 	$(NULL)
 
 LOCAL_INCLUDES := \