diff --git a/client/common/cmdline.h b/client/common/cmdline.h
index 66fe37923..7cd325ed6 100644
--- a/client/common/cmdline.h
+++ b/client/common/cmdline.h
@@ -321,7 +321,7 @@ static const COMMAND_LINE_ARGUMENT_A global_cmd_args[] = {
 	  "[DEPRECATED, use /list:monitor] List detected monitors" },
 #endif
 	{ "monitors", COMMAND_LINE_VALUE_REQUIRED, "<id>[,<id>[,...]]", NULL, NULL, -1, NULL,
-	  "Select monitors to use" },
+	  "Select monitors to use (only effective in fullscreen or multimonitor mode)" },
 	{ "mouse-motion", COMMAND_LINE_VALUE_BOOL, NULL, BoolValueTrue, NULL, -1, NULL,
 	  "Send mouse motion" },
 	{ "mouse-relative", COMMAND_LINE_VALUE_BOOL, NULL, BoolValueFalse, NULL, -1, NULL,