From 0264ef094a79c828e72e03052b9969cd80b28d16 Mon Sep 17 00:00:00 2001
From: nicm <nicm>
Date: Fri, 12 May 2017 23:06:43 +0000
Subject: [PATCH] Can scroll away full lines to clear them too.

---
 tty.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/tty.c b/tty.c
index 58a4028c..a03e9a0d 100644
--- a/tty.c
+++ b/tty.c
@@ -830,12 +830,25 @@ tty_clear_area(struct tty *tty, const struct window_pane *wp, u_int py,
 			return;
 		}
 
+		/* Full lines can be scrolled away to clear them. */
+		if (px == 0 &&
+		    px + nx > tty->sx &&
+		    ny > 2 &&
+		    tty_term_has(tty->term, TTYC_CSR) &&
+		    tty_term_has(tty->term, TTYC_INDN)) {
+			tty_region(tty, py, py + ny - 1);
+			tty_margin_off(tty);
+			tty_putcode1(tty, TTYC_INDN, ny);
+			return;
+		}
+
 		/*
 		 * If margins are supported, can just scroll the area off to
 		 * clear it.
 		 */
 		if (nx > 2 &&
 		    ny > 2 &&
+		    tty_term_has(tty->term, TTYC_CSR) &&
 		    tty_use_margin(tty) &&
 		    tty_term_has(tty->term, TTYC_INDN)) {
 			tty_region(tty, py, py + ny - 1);