diff --git a/mozilla/mailnews/ui/messenger/resources/makefile.win b/mozilla/mailnews/ui/messenger/resources/makefile.win
index 6df59d7f690..53f3f540195 100644
--- a/mozilla/mailnews/ui/messenger/resources/makefile.win
+++ b/mozilla/mailnews/ui/messenger/resources/makefile.win
@@ -29,6 +29,7 @@ install::
 	$(MAKE_INSTALL) folderPane.xul	$(DIST)\bin\res\samples
 	$(MAKE_INSTALL) folderPane.css	$(DIST)\bin\res\samples
 	$(MAKE_INSTALL) threadPane.xul  $(DIST)\bin\res\samples
+	$(MAKE_INSTALL) threadPane.css	$(DIST)\bin\res\samples
 	$(MAKE_INSTALL) message.html	$(DIST)\bin\res\samples
 
 clobber::