From 9f2db6a0af92cb88a029ef8fad003923c0b32936 Mon Sep 17 00:00:00 2001
From: nicm <nicm>
Date: Mon, 20 Aug 2018 13:51:09 +0000
Subject: [PATCH] Fix problems with page scrolling in copy mode, GitHub issue
 1440 from Amos Bird.

---
 window-copy.c | 22 ++++++++++++----------
 1 file changed, 12 insertions(+), 10 deletions(-)

diff --git a/window-copy.c b/window-copy.c
index c2d9b9ad..5d533931 100644
--- a/window-copy.c
+++ b/window-copy.c
@@ -353,9 +353,6 @@ window_copy_pageup(struct window_pane *wp, int half_page)
 	oy = screen_hsize(data->backing) + data->cy - data->oy;
 	ox = window_copy_find_length(wp, oy);
 
-	if (data->lineflag == LINE_SEL_LEFT_RIGHT && oy == data->sely)
-		window_copy_other_end(wp);
-
 	if (data->cx != ox) {
 		data->lastcx = data->cx;
 		data->lastsx = ox;
@@ -370,9 +367,13 @@ window_copy_pageup(struct window_pane *wp, int half_page)
 			n = screen_size_y(s) - 2;
 	}
 
-	if (data->oy + n > screen_hsize(data->backing))
+	if (data->oy + n > screen_hsize(data->backing)) {
 		data->oy = screen_hsize(data->backing);
-	else
+		if (data->cy < n)
+			data->cy = 0;
+		else
+			data->cy -= n;
+	} else
 		data->oy += n;
 
 	if (data->screen.sel == NULL || !data->rectflag) {
@@ -397,9 +398,6 @@ window_copy_pagedown(struct window_pane *wp, int half_page, int scroll_exit)
 	oy = screen_hsize(data->backing) + data->cy - data->oy;
 	ox = window_copy_find_length(wp, oy);
 
-	if (data->lineflag == LINE_SEL_RIGHT_LEFT && oy == data->sely)
-		window_copy_other_end(wp);
-
 	if (data->cx != ox) {
 		data->lastcx = data->cx;
 		data->lastsx = ox;
@@ -414,9 +412,13 @@ window_copy_pagedown(struct window_pane *wp, int half_page, int scroll_exit)
 			n = screen_size_y(s) - 2;
 	}
 
-	if (data->oy < n)
+	if (data->oy < n) {
 		data->oy = 0;
-	else
+		if (data->cy + (n - data->oy) >= screen_size_y(data->backing))
+			data->cy = screen_size_y(data->backing) - 1;
+		else
+			data->cy += n - data->oy;
+	} else
 		data->oy -= n;
 
 	if (data->screen.sel == NULL || !data->rectflag) {