diff --git a/mozilla/themes/Makefile.in b/mozilla/themes/Makefile.in
index 30149c7557e..de60eb99b68 100644
--- a/mozilla/themes/Makefile.in
+++ b/mozilla/themes/Makefile.in
@@ -26,7 +26,11 @@ VPATH		= @srcdir@
 
 include $(DEPTH)/config/autoconf.mk
 
-DIRS		= classic modern 
+DIRS		= classic
+
+ifndef MOZ_PHOENIX
+DIRS		+= modern 
+endif
 
 include $(topsrcdir)/config/rules.mk