diff --git a/src/cdmrc b/src/cdmrc
index 3631ffe..1d0525c 100644
--- a/src/cdmrc
+++ b/src/cdmrc
@@ -39,6 +39,7 @@ countfrom=0
 display=0
 
 # Where should the first X tty be spawned?
+# special value 'keep' causes to run X in current tty
 xtty=7
 
 # Should cdm(1) stick to the specified display?