diff --git a/src/option.c b/src/option.c
index 9573351..5ce5218 100644
--- a/src/option.c
+++ b/src/option.c
@@ -3555,7 +3555,7 @@
     // if p_ch changed value, change the command line height
     else if (pp == &p_ch)
     {
-	if (p_ch < 0)
+	if (p_ch < 1)
 	{
 	    errmsg = e_argument_must_be_positive;
 	    p_ch = 1;