--- a/lisp/prim/fill.el	Mon Aug 13 10:00:35 2007 +0200
+++ b/lisp/prim/fill.el	Mon Aug 13 10:01:22 2007 +0200
@@ -43,7 +43,9 @@
 A value of nil means that any change in indentation starts a new paragraph.")
 
 (defconst sentence-end-double-space t
-  "*Non-nil means a single space does not end a sentence.")
+  "*Non-nil means a single space does not end a sentence.
+This variable applies only to filling, not motion commands.  To
+change the behavior of motion commands, see `sentence-end'.")
 
 (defconst colon-double-space nil
   "*Non-nil means put two spaces after a colon when filling.")