From 8d2fcd3518d3e2fdfa9f3e0a62004cf57f94108c Mon Sep 17 00:00:00 2001
From: Junegunn Choi <junegunn.c@gmail.com>
Date: Fri, 29 Mar 2019 15:12:46 +0900
Subject: [PATCH] Avoid unnecessary redraw of the preview window

---
 src/terminal.go | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/src/terminal.go b/src/terminal.go
index ca811c4..3175aaa 100644
--- a/src/terminal.go
+++ b/src/terminal.go
@@ -1652,9 +1652,12 @@ func (t *Terminal) Loop() {
 			}
 		}
 		scrollPreview := func(amount int) {
-			t.previewer.offset = util.Constrain(
+			newOffset := util.Constrain(
 				t.previewer.offset+amount, 0, t.previewer.lines-1)
-			req(reqPreviewRefresh)
+			if t.previewer.offset != newOffset {
+				t.previewer.offset = newOffset
+				req(reqPreviewRefresh)
+			}
 		}
 		for key, ret := range t.expect {
 			if keyMatch(key, event) {