diff --git a/lib/htmldlgs/htmldlgs.h b/lib/htmldlgs/htmldlgs.h
index 0c84ba7c9914..5e54d3ea5b02 100644
--- a/lib/htmldlgs/htmldlgs.h
+++ b/lib/htmldlgs/htmldlgs.h
@@ -26,11 +26,7 @@
  */
 
 #include "ntypes.h"
-#ifndef NSPR20
-#include "prarena.h"
-#else
 #include "plarena.h"
-#endif
 
 XP_BEGIN_PROTOS