diff --git a/runtime/doc/options.txt b/runtime/doc/options.txt
index 6d2b3242db..48e9013052 100644
--- a/runtime/doc/options.txt
+++ b/runtime/doc/options.txt
@@ -2292,7 +2292,9 @@ A jump table for the options with a short description can be found at |Q_op|.
 
 	   noselect Same as "noinsert", except that no menu item is
 		    pre-selected.  If both "noinsert" and "noselect" are
-		    present, "noselect" has precedence.
+		    present, "noselect" takes precedence.  This options is
+		    enabled automatically when 'autocomplete' is on, unless
+		    "preinsert" is also enabled.
 
 	   nosort   Disable sorting of completion candidates based on fuzzy
 		    scores when "fuzzy" is enabled.  Candidates will appear