diff --git a/runtime/doc/testing.txt b/runtime/doc/testing.txt
index 4e85bdc..64b8697 100644
--- a/runtime/doc/testing.txt
+++ b/runtime/doc/testing.txt
@@ -165,6 +165,8 @@
 				terminals
 		no_wait_return	set the "no_wait_return" flag.  Not restored
 				with "ALL".
+		ui_delay     time in msec to use in ui_delay(); overrules a
+			     wait time of up to 3 seconds for messages
 		term_props   reset all terminal properties when the version
 			     string is detected
 		ALL	     clear all overrides ({val} is not used)