diff --git a/collects/scribblings/htdp-langs/htdp-langs.scrbl b/collects/scribblings/htdp-langs/htdp-langs.scrbl
index 5d01540e59..030a4cc4d8 100644
--- a/collects/scribblings/htdp-langs/htdp-langs.scrbl
+++ b/collects/scribblings/htdp-langs/htdp-langs.scrbl
@@ -1,5 +1,6 @@
 #lang scribble/doc
 @(require "common.ss")
+@(require (for-label lang/htdp-beginner))
 
 @title{@italic{How to Design Programs} Languages}
 
@@ -7,6 +8,15 @@ The languages documented in this manual are provided by DrScheme to be
 used with the @italic{@link["http://www.htdp.org/"]{How to Design
 Programs}} book.
 
+When programs in these languages are run in DrScheme, any part of the
+program that was not run is highlighted in orange and black. These
+colors are intended to give the programmer feedback about the parts of
+the program that have not been tested. To avoid seeing these colors,
+use @scheme[check-expect] to test your program. Of course, just
+because you see no colors, does not mean that your program has been
+fully tested; it simply means that each part of the program been run
+(at least once).
+
 @table-of-contents[]
 
 @;------------------------------------------------------------------------