Mouse support on the scrollbars, from Michael Grant.

7 files changed, 641 insertions, 77 deletions

diff --git a/usr.bin/tmux/cmd-copy-mode.c b/usr.bin/tmux/cmd-copy-mode.c
index a9110cf87cb..b173d613597 100644
--- a/usr.bin/tmux/cmd-copy-mode.c
+++ b/usr.bin/tmux/cmd-copy-mode.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: cmd-copy-mode.c,v 1.48 2024/08/26 07:09:34 nicm Exp $ */
+/* $OpenBSD: cmd-copy-mode.c,v 1.49 2024/11/12 09:32:56 nicm Exp $ */
 
 /*
  * Copyright (c) 2007 Nicholas Marriott <nicholas.marriott@gmail.com>
@@ -30,8 +30,8 @@ const struct cmd_entry cmd_copy_mode_entry = {
 	.name = "copy-mode",
 	.alias = NULL,
 
-	.args = { "deHMs:t:uq", 0, 0, NULL },
-	.usage = "[-deHMuq] [-s src-pane] " CMD_TARGET_PANE_USAGE,
+	.args = { "deHMqSs:t:u", 0, 0, NULL },
+	.usage = "[-deHMqSu] [-s src-pane] " CMD_TARGET_PANE_USAGE,
 
 	.source =  { 's', CMD_FIND_PANE, 0 },
 	.target = { 't', CMD_FIND_PANE, 0 },
@@ -92,7 +92,12 @@ cmd_copy_mode_exec(struct cmd *self, struct cmdq_item *item)
 	if (args_has(args, 'u'))
 		window_copy_pageup(wp, 0);
 	if (args_has(args, 'd'))
-                window_copy_pagedown(wp, 0, args_has(args, 'e'));
+		window_copy_pagedown(wp, 0, args_has(args, 'e'));
+	if (args_has(args, 'S')) {
+		window_copy_scroll(wp, c->tty.mouse_slider_mpos, event->m.y,
+		    args_has(args, 'e'));
+		return (CMD_RETURN_NORMAL);
+	}
 
 	return (CMD_RETURN_NORMAL);
 }
diff --git a/usr.bin/tmux/key-bindings.c b/usr.bin/tmux/key-bindings.c
index 5f14aa3748f..c248003bd8b 100644
--- a/usr.bin/tmux/key-bindings.c
+++ b/usr.bin/tmux/key-bindings.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: key-bindings.c,v 1.150 2024/10/04 07:03:08 nicm Exp $ */
+/* $OpenBSD: key-bindings.c,v 1.151 2024/11/12 09:32:56 nicm Exp $ */
 
 /*
  * Copyright (c) 2007 Nicholas Marriott <nicholas.marriott@gmail.com>
@@ -478,6 +478,11 @@ key_bindings_init(void)
 		"bind -n MouseDown3Pane { if -Ft= '#{||:#{mouse_any_flag},#{&&:#{pane_in_mode},#{?#{m/r:(copy|view)-mode,#{pane_mode}},0,1}}}' { select-pane -t=; send -M } { display-menu -t= -xM -yM -T '#[align=centre]#{pane_index} (#{pane_id})' " DEFAULT_PANE_MENU " } }",
 		"bind -n M-MouseDown3Pane { display-menu -t= -xM -yM -T '#[align=centre]#{pane_index} (#{pane_id})' " DEFAULT_PANE_MENU " }",
 
+		/* Mouse on scrollbar. */
+		"bind -n MouseDown1ScrollbarUp { copy-mode -u }",
+		"bind -n MouseDown1ScrollbarDown { copy-mode -d }",
+		"bind -n MouseDrag1ScrollbarSlider { copy-mode -S }",
+
 		/* Copy mode (emacs) keys. */
 		"bind -Tcopy-mode C-Space { send -X begin-selection }",
 		"bind -Tcopy-mode C-a { send -X start-of-line }",
diff --git a/usr.bin/tmux/screen-redraw.c b/usr.bin/tmux/screen-redraw.c
index cbda4a6954d..0326775baf1 100644
--- a/usr.bin/tmux/screen-redraw.c
+++ b/usr.bin/tmux/screen-redraw.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: screen-redraw.c,v 1.100 2024/11/05 09:41:17 nicm Exp $ */
+/* $OpenBSD: screen-redraw.c,v 1.101 2024/11/12 09:32:56 nicm Exp $ */
 
 /*
  * Copyright (c) 2007 Nicholas Marriott <nicholas.marriott@gmail.com>
@@ -1001,6 +1001,10 @@ screen_redraw_draw_pane_scrollbar(struct screen_redraw_ctx *ctx,
 
 	screen_redraw_draw_scrollbar(ctx, wp, sb_pos, sb_x, sb_y, sb_h,
 	    slider_h, slider_y);
+
+	/* Store current position and height of the slider */
+	wp->sb_slider_y = slider_y;  /* top of slider y pos in scrollbar */
+	wp->sb_slider_h = slider_h;  /* height of slider */
 }
 
 static void
diff --git a/usr.bin/tmux/server-client.c b/usr.bin/tmux/server-client.c
index 1493b6726a5..9af2a290382 100644
--- a/usr.bin/tmux/server-client.c
+++ b/usr.bin/tmux/server-client.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: server-client.c,v 1.415 2024/11/05 09:41:17 nicm Exp $ */
+/* $OpenBSD: server-client.c,v 1.416 2024/11/12 09:32:56 nicm Exp $ */
 
 /*
  * Copyright (c) 2009 Nicholas Marriott <nicholas.marriott@gmail.com>
@@ -576,10 +576,12 @@ server_client_check_mouse(struct client *c, struct key_event *event)
 {
 	struct mouse_event	*m = &event->m;
 	struct session		*s = c->session, *fs;
+	struct options		*wo = s->curw->window->options;
 	struct winlink		*fwl;
 	struct window_pane	*wp, *fwp;
-	u_int			 x, y, b, sx, sy, px, py;
-	int			 ignore = 0;
+	u_int			 x, y, b, sx, sy, px, py, line = 0, sb_pos;
+	u_int			 sl_top, sl_bottom, sl_mpos = 0;
+	int			 ignore = 0, sb, sb_w, pane_status;
 	key_code		 key;
 	struct timeval		 tv;
 	struct style_range	*sr;
@@ -598,7 +600,10 @@ server_client_check_mouse(struct client *c, struct key_event *event)
 	       STATUS_LEFT,
 	       STATUS_RIGHT,
 	       STATUS_DEFAULT,
-	       BORDER } where = NOWHERE;
+	       BORDER,
+	       SCROLLBAR_UP,
+	       SCROLLBAR_SLIDER,
+	       SCROLLBAR_DOWN } where = NOWHERE;
 
 	log_debug("%s mouse %02x at %u,%u (last %u,%u) (%d)", c->name, m->b,
 	    m->x, m->y, m->lx, m->ly, c->tty.mouse_drag_flag);
@@ -747,54 +752,114 @@ have_event:
 		}
 	}
 
-	/* Not on status line. Adjust position and check for border or pane. */
+	/*
+	 * Not on status line. Adjust position and check for border, pane, or
+	 * scrollbar.
+	 */
 	if (where == NOWHERE) {
-		px = x;
-		if (m->statusat == 0 && y >= m->statuslines)
-			py = y - m->statuslines;
-		else if (m->statusat > 0 && y >= (u_int)m->statusat)
-			py = m->statusat - 1;
-		else
-			py = y;
-
-		tty_window_offset(&c->tty, &m->ox, &m->oy, &sx, &sy);
-		log_debug("mouse window @%u at %u,%u (%ux%u)",
-		    s->curw->window->id, m->ox, m->oy, sx, sy);
-		if (px > sx || py > sy)
-			return (KEYC_UNKNOWN);
-		px = px + m->ox;
-		py = py + m->oy;
-
-		/* Try the pane borders if not zoomed. */
-		if (~s->curw->window->flags & WINDOW_ZOOMED) {
-			TAILQ_FOREACH(wp, &s->curw->window->panes, entry) {
-				if ((wp->xoff + wp->sx == px &&
-				    wp->yoff <= 1 + py &&
-				    wp->yoff + wp->sy >= py) ||
-				    (wp->yoff + wp->sy == py &&
-				    wp->xoff <= 1 + px &&
-				    wp->xoff + wp->sx >= px))
-					break;
-			}
-			if (wp != NULL)
-				where = BORDER;
-		}
+		if (c->tty.mouse_scrolling_flag)
+			where = SCROLLBAR_SLIDER;
+		else {
+			px = x;
+			if (m->statusat == 0 && y >= m->statuslines)
+				py = y - m->statuslines;
+			else if (m->statusat > 0 && y >= (u_int)m->statusat)
+				py = m->statusat - 1;
+			else
+				py = y;
+
+			tty_window_offset(&c->tty, &m->ox, &m->oy, &sx, &sy);
+			log_debug("mouse window @%u at %u,%u (%ux%u)",
+				  s->curw->window->id, m->ox, m->oy, sx, sy);
+			if (px > sx || py > sy)
+				return (KEYC_UNKNOWN);
+			px = px + m->ox;
+			py = py + m->oy;
 
-		/* Otherwise try inside the pane. */
-		if (where == NOWHERE) {
+			/* Try inside the pane. */
 			wp = window_get_active_at(s->curw->window, px, py);
-			if (wp != NULL)
-				where = PANE;
-			else
+			if (wp == NULL)
 				return (KEYC_UNKNOWN);
+
+			/* Try the scrollbar next to a pane. */
+			sb = options_get_number(wo, "pane-scrollbars");
+			sb_pos = options_get_number(wo,
+			    "pane-scrollbars-position");
+			if (sb == PANE_SCROLLBARS_ALWAYS ||
+			    (sb == PANE_SCROLLBARS_MODAL &&
+			    window_pane_mode(wp) != WINDOW_PANE_NO_MODE))
+				sb_w = PANE_SCROLLBARS_WIDTH;
+			else
+				sb_w = 0;
+			pane_status = options_get_number(wo,
+			    "pane-border-status");
+			if (pane_status == PANE_STATUS_TOP)
+				line = wp->yoff - 1;
+			else if (pane_status == PANE_STATUS_BOTTOM)
+				line = wp->yoff + wp->sy;
+
+			/*
+			 * Check if py could lie within a scrollbar. If the
+			 * pane is at the top, then py is 0; if not then the
+			 * top, then yoff to yoff + sy.
+			 */
+			if ((pane_status != PANE_STATUS_OFF && py != line) ||
+			    (wp->yoff == 0 && py < wp->sy) ||
+			    (py >= wp->yoff && py < wp->yoff + wp->sy)) {
+				if ((sb_pos == PANE_SCROLLBARS_RIGHT &&
+				    (px >= wp->xoff + wp->sx &&
+				    px < wp->xoff + wp->sx + sb_w)) ||
+				    (sb_pos == PANE_SCROLLBARS_LEFT &&
+				    (px >= wp->xoff - sb_w &&
+				    px < wp->xoff))) {
+					sl_top = wp->yoff + wp->sb_slider_y;
+					sl_bottom = (wp->yoff +
+					    wp->sb_slider_y +
+					    wp->sb_slider_h - 1);
+					if (py < sl_top)
+						where = SCROLLBAR_UP;
+					else if (py >= sl_top &&
+					    py <= sl_bottom) {
+						where = SCROLLBAR_SLIDER;
+						sl_mpos = (py -
+						    wp->sb_slider_y - wp->yoff);
+					} else /* py > sl_bottom */
+						where = SCROLLBAR_DOWN;
+				} else
+					where = PANE;
+			} else {
+				/* Try the pane borders if not zoomed. */
+				if (~s->curw->window->flags & WINDOW_ZOOMED) {
+					TAILQ_FOREACH(wp,
+					    &s->curw->window->panes, entry) {
+						if ((wp->xoff + wp->sx == px &&
+						    wp->yoff <= 1 + py &&
+						    wp->yoff + wp->sy >= py) ||
+						    (wp->yoff + wp->sy == py &&
+						    wp->xoff <= 1 + px &&
+						    wp->xoff + wp->sx >= px))
+							break;
+					}
+					if (wp != NULL)
+						where = BORDER;
+				}
+			}
+			if (where == PANE) {
+				log_debug("mouse %u,%u on pane %%%u", x, y,
+				    wp->id);
+			} else if (where == BORDER)
+				log_debug("mouse on pane %%%u border", wp->id);
+			else if (where == SCROLLBAR_UP ||
+			    where == SCROLLBAR_SLIDER ||
+			    where == SCROLLBAR_DOWN) {
+				log_debug("mouse on pane %%%u scrollbar",
+				    wp->id);
+			}
+			m->wp = wp->id;
+			m->w = wp->window->id;
 		}
-		if (where == PANE)
-			log_debug("mouse %u,%u on pane %%%u", x, y, wp->id);
-		else if (where == BORDER)
-			log_debug("mouse on pane %%%u border", wp->id);
-		m->wp = wp->id;
-		m->w = wp->window->id;
-	}
+	} else
+		m->wp = -1;
 
 	/* Stop dragging if needed. */
 	if (type != DRAG && type != WHEEL && c->tty.mouse_drag_flag != 0) {
@@ -803,6 +868,7 @@ have_event:
 
 		c->tty.mouse_drag_update = NULL;
 		c->tty.mouse_drag_release = NULL;
+		c->tty.mouse_scrolling_flag = 0;
 
 		/*
 		 * End a mouse drag by passing a MouseDragEnd key corresponding
@@ -820,6 +886,8 @@ have_event:
 				key = KEYC_MOUSEDRAGEND1_STATUS_RIGHT;
 			if (where == STATUS_DEFAULT)
 				key = KEYC_MOUSEDRAGEND1_STATUS_DEFAULT;
+			if (where == SCROLLBAR_SLIDER)
+				key = KEYC_MOUSEDRAGEND1_SCROLLBAR_SLIDER;
 			if (where == BORDER)
 				key = KEYC_MOUSEDRAGEND1_BORDER;
 			break;
@@ -834,6 +902,8 @@ have_event:
 				key = KEYC_MOUSEDRAGEND2_STATUS_RIGHT;
 			if (where == STATUS_DEFAULT)
 				key = KEYC_MOUSEDRAGEND2_STATUS_DEFAULT;
+			if (where == SCROLLBAR_SLIDER)
+				key = KEYC_MOUSEDRAGEND2_SCROLLBAR_SLIDER;
 			if (where == BORDER)
 				key = KEYC_MOUSEDRAGEND2_BORDER;
 			break;
@@ -848,6 +918,8 @@ have_event:
 				key = KEYC_MOUSEDRAGEND3_STATUS_RIGHT;
 			if (where == STATUS_DEFAULT)
 				key = KEYC_MOUSEDRAGEND3_STATUS_DEFAULT;
+			if (where == SCROLLBAR_SLIDER)
+				key = KEYC_MOUSEDRAGEND3_SCROLLBAR_SLIDER;
 			if (where == BORDER)
 				key = KEYC_MOUSEDRAGEND3_BORDER;
 			break;
@@ -862,6 +934,8 @@ have_event:
 				key = KEYC_MOUSEDRAGEND6_STATUS_RIGHT;
 			if (where == STATUS_DEFAULT)
 				key = KEYC_MOUSEDRAGEND6_STATUS_DEFAULT;
+			if (where == SCROLLBAR_SLIDER)
+				key = KEYC_MOUSEDRAGEND6_SCROLLBAR_SLIDER;
 			if (where == BORDER)
 				key = KEYC_MOUSEDRAGEND6_BORDER;
 			break;
@@ -876,6 +950,8 @@ have_event:
 				key = KEYC_MOUSEDRAGEND7_STATUS_RIGHT;
 			if (where == STATUS_DEFAULT)
 				key = KEYC_MOUSEDRAGEND7_STATUS_DEFAULT;
+			if (where == SCROLLBAR_SLIDER)
+				key = KEYC_MOUSEDRAGEND7_SCROLLBAR_SLIDER;
 			if (where == BORDER)
 				key = KEYC_MOUSEDRAGEND7_BORDER;
 			break;
@@ -890,6 +966,8 @@ have_event:
 				key = KEYC_MOUSEDRAGEND8_STATUS_RIGHT;
 			if (where == STATUS_DEFAULT)
 				key = KEYC_MOUSEDRAGEND8_STATUS_DEFAULT;
+			if (where == SCROLLBAR_SLIDER)
+				key = KEYC_MOUSEDRAGEND8_SCROLLBAR_SLIDER;
 			if (where == BORDER)
 				key = KEYC_MOUSEDRAGEND8_BORDER;
 			break;
@@ -904,6 +982,8 @@ have_event:
 				key = KEYC_MOUSEDRAGEND9_STATUS_RIGHT;
 			if (where == STATUS_DEFAULT)
 				key = KEYC_MOUSEDRAGEND9_STATUS_DEFAULT;
+			if (where == SCROLLBAR_SLIDER)
+				key = KEYC_MOUSEDRAGEND9_SCROLLBAR_SLIDER;
 			if (where == BORDER)
 				key = KEYC_MOUSEDRAGEND9_BORDER;
 			break;
@@ -918,6 +998,8 @@ have_event:
 				key = KEYC_MOUSEDRAGEND10_STATUS_RIGHT;
 			if (where == STATUS_DEFAULT)
 				key = KEYC_MOUSEDRAGEND10_STATUS_DEFAULT;
+			if (where == SCROLLBAR_SLIDER)
+				key = KEYC_MOUSEDRAGEND10_SCROLLBAR_SLIDER;
 			if (where == BORDER)
 				key = KEYC_MOUSEDRAGEND10_BORDER;
 			break;
@@ -932,6 +1014,8 @@ have_event:
 				key = KEYC_MOUSEDRAGEND11_STATUS_RIGHT;
 			if (where == STATUS_DEFAULT)
 				key = KEYC_MOUSEDRAGEND11_STATUS_DEFAULT;
+			if (where == SCROLLBAR_SLIDER)
+				key = KEYC_MOUSEDRAGEND11_SCROLLBAR_SLIDER;
 			if (where == BORDER)
 				key = KEYC_MOUSEDRAGEND11_BORDER;
 			break;
@@ -940,6 +1024,7 @@ have_event:
 			break;
 		}
 		c->tty.mouse_drag_flag = 0;
+		c->tty.mouse_slider_mpos = -1;
 		goto out;
 	}
 
@@ -978,6 +1063,12 @@ have_event:
 					key = KEYC_MOUSEDRAG1_STATUS_RIGHT;
 				if (where == STATUS_DEFAULT)
 					key = KEYC_MOUSEDRAG1_STATUS_DEFAULT;
+				if (where == SCROLLBAR_UP)
+					key = KEYC_MOUSEDRAG1_SCROLLBAR_UP;
+				if (where == SCROLLBAR_SLIDER)
+					key = KEYC_MOUSEDRAG1_SCROLLBAR_SLIDER;
+				if (where == SCROLLBAR_DOWN)
+					key = KEYC_MOUSEDRAG1_SCROLLBAR_DOWN;
 				if (where == BORDER)
 					key = KEYC_MOUSEDRAG1_BORDER;
 				break;
@@ -992,6 +1083,12 @@ have_event:
 					key = KEYC_MOUSEDRAG2_STATUS_RIGHT;
 				if (where == STATUS_DEFAULT)
 					key = KEYC_MOUSEDRAG2_STATUS_DEFAULT;
+				if (where == SCROLLBAR_UP)
+					key = KEYC_MOUSEDRAG2_SCROLLBAR_UP;
+				if (where == SCROLLBAR_SLIDER)
+					key = KEYC_MOUSEDRAG2_SCROLLBAR_SLIDER;
+				if (where == SCROLLBAR_DOWN)
+					key = KEYC_MOUSEDRAG2_SCROLLBAR_DOWN;
 				if (where == BORDER)
 					key = KEYC_MOUSEDRAG2_BORDER;
 				break;
@@ -1006,6 +1103,12 @@ have_event:
 					key = KEYC_MOUSEDRAG3_STATUS_RIGHT;
 				if (where == STATUS_DEFAULT)
 					key = KEYC_MOUSEDRAG3_STATUS_DEFAULT;
+				if (where == SCROLLBAR_UP)
+					key = KEYC_MOUSEDRAG3_SCROLLBAR_UP;
+				if (where == SCROLLBAR_SLIDER)
+					key = KEYC_MOUSEDRAG3_SCROLLBAR_SLIDER;
+				if (where == SCROLLBAR_DOWN)
+					key = KEYC_MOUSEDRAG3_SCROLLBAR_DOWN;
 				if (where == BORDER)
 					key = KEYC_MOUSEDRAG3_BORDER;
 				break;
@@ -1020,6 +1123,12 @@ have_event:
 					key = KEYC_MOUSEDRAG6_STATUS_RIGHT;
 				if (where == STATUS_DEFAULT)
 					key = KEYC_MOUSEDRAG6_STATUS_DEFAULT;
+				if (where == SCROLLBAR_UP)
+					key = KEYC_MOUSEDRAG6_SCROLLBAR_UP;
+				if (where == SCROLLBAR_SLIDER)
+					key = KEYC_MOUSEDRAG6_SCROLLBAR_SLIDER;
+				if (where == SCROLLBAR_DOWN)
+					key = KEYC_MOUSEDRAG6_SCROLLBAR_DOWN;
 				if (where == BORDER)
 					key = KEYC_MOUSEDRAG6_BORDER;
 				break;
@@ -1034,6 +1143,12 @@ have_event:
 					key = KEYC_MOUSEDRAG7_STATUS_RIGHT;
 				if (where == STATUS_DEFAULT)
 					key = KEYC_MOUSEDRAG7_STATUS_DEFAULT;
+				if (where == SCROLLBAR_UP)
+					key = KEYC_MOUSEDRAG7_SCROLLBAR_UP;
+				if (where == SCROLLBAR_SLIDER)
+					key = KEYC_MOUSEDRAG7_SCROLLBAR_SLIDER;
+				if (where == SCROLLBAR_DOWN)
+					key = KEYC_MOUSEDRAG7_SCROLLBAR_DOWN;
 				if (where == BORDER)
 					key = KEYC_MOUSEDRAG7_BORDER;
 				break;
@@ -1048,6 +1163,12 @@ have_event:
 					key = KEYC_MOUSEDRAG8_STATUS_RIGHT;
 				if (where == STATUS_DEFAULT)
 					key = KEYC_MOUSEDRAG8_STATUS_DEFAULT;
+				if (where == SCROLLBAR_UP)
+					key = KEYC_MOUSEDRAG8_SCROLLBAR_UP;
+				if (where == SCROLLBAR_SLIDER)
+					key = KEYC_MOUSEDRAG8_SCROLLBAR_SLIDER;
+				if (where == SCROLLBAR_DOWN)
+					key = KEYC_MOUSEDRAG8_SCROLLBAR_DOWN;
 				if (where == BORDER)
 					key = KEYC_MOUSEDRAG8_BORDER;
 				break;
@@ -1062,6 +1183,12 @@ have_event:
 					key = KEYC_MOUSEDRAG9_STATUS_RIGHT;
 				if (where == STATUS_DEFAULT)
 					key = KEYC_MOUSEDRAG9_STATUS_DEFAULT;
+				if (where == SCROLLBAR_UP)
+					key = KEYC_MOUSEDRAG9_SCROLLBAR_UP;
+				if (where == SCROLLBAR_SLIDER)
+					key = KEYC_MOUSEDRAG9_SCROLLBAR_SLIDER;
+				if (where == SCROLLBAR_DOWN)
+					key = KEYC_MOUSEDRAG9_SCROLLBAR_DOWN;
 				if (where == BORDER)
 					key = KEYC_MOUSEDRAG9_BORDER;
 				break;
@@ -1076,6 +1203,12 @@ have_event:
 					key = KEYC_MOUSEDRAG10_STATUS_RIGHT;
 				if (where == STATUS_DEFAULT)
 					key = KEYC_MOUSEDRAG10_STATUS_DEFAULT;
+				if (where == SCROLLBAR_UP)
+					key = KEYC_MOUSEDRAG10_SCROLLBAR_UP;
+				if (where == SCROLLBAR_SLIDER)
+					key = KEYC_MOUSEDRAG10_SCROLLBAR_SLIDER;
+				if (where == SCROLLBAR_DOWN)
+					key = KEYC_MOUSEDRAG10_SCROLLBAR_DOWN;
 				if (where == BORDER)
 					key = KEYC_MOUSEDRAG10_BORDER;
 				break;
@@ -1090,6 +1223,12 @@ have_event:
 					key = KEYC_MOUSEDRAG11_STATUS_RIGHT;
 				if (where == STATUS_DEFAULT)
 					key = KEYC_MOUSEDRAG11_STATUS_DEFAULT;
+				if (where == SCROLLBAR_UP)
+					key = KEYC_MOUSEDRAG11_SCROLLBAR_UP;
+				if (where == SCROLLBAR_SLIDER)
+					key = KEYC_MOUSEDRAG11_SCROLLBAR_SLIDER;
+				if (where == SCROLLBAR_DOWN)
+					key = KEYC_MOUSEDRAG11_SCROLLBAR_DOWN;
 				if (where == BORDER)
 					key = KEYC_MOUSEDRAG11_BORDER;
 				break;
@@ -1098,9 +1237,16 @@ have_event:
 
 		/*
 		 * Begin a drag by setting the flag to a non-zero value that
-		 * corresponds to the mouse button in use.
+		 * corresponds to the mouse button in use. If starting to drag
+		 * the scrollbar, store the relative position in the slider
+		 * where the user grabbed.
 		 */
 		c->tty.mouse_drag_flag = MOUSE_BUTTONS(b) + 1;
+		if (c->tty.mouse_scrolling_flag == 0 &&
+		    where == SCROLLBAR_SLIDER) {
+			c->tty.mouse_scrolling_flag = 1;
+			c->tty.mouse_slider_mpos = sl_mpos;
+		}
 		break;
 	case WHEEL:
 		if (MOUSE_BUTTONS(b) == MOUSE_WHEEL_UP) {
@@ -1144,6 +1290,12 @@ have_event:
 				key = KEYC_MOUSEUP1_STATUS_RIGHT;
 			if (where == STATUS_DEFAULT)
 				key = KEYC_MOUSEUP1_STATUS_DEFAULT;
+			if (where == SCROLLBAR_UP)
+				key = KEYC_MOUSEUP1_SCROLLBAR_UP;
+			if (where == SCROLLBAR_SLIDER)
+				key = KEYC_MOUSEUP1_SCROLLBAR_SLIDER;
+			if (where == SCROLLBAR_DOWN)
+				key = KEYC_MOUSEUP1_SCROLLBAR_DOWN;
 			if (where == BORDER)
 				key = KEYC_MOUSEUP1_BORDER;
 			break;
@@ -1158,6 +1310,12 @@ have_event:
 				key = KEYC_MOUSEUP2_STATUS_RIGHT;
 			if (where == STATUS_DEFAULT)
 				key = KEYC_MOUSEUP2_STATUS_DEFAULT;
+			if (where == SCROLLBAR_UP)
+				key = KEYC_MOUSEUP2_SCROLLBAR_UP;
+			if (where == SCROLLBAR_SLIDER)
+				key = KEYC_MOUSEUP2_SCROLLBAR_SLIDER;
+			if (where == SCROLLBAR_DOWN)
+				key = KEYC_MOUSEUP2_SCROLLBAR_DOWN;
 			if (where == BORDER)
 				key = KEYC_MOUSEUP2_BORDER;
 			break;
@@ -1172,6 +1330,12 @@ have_event:
 				key = KEYC_MOUSEUP3_STATUS_RIGHT;
 			if (where == STATUS_DEFAULT)
 				key = KEYC_MOUSEUP3_STATUS_DEFAULT;
+			if (where == SCROLLBAR_UP)
+				key = KEYC_MOUSEUP3_SCROLLBAR_UP;
+			if (where == SCROLLBAR_SLIDER)
+				key = KEYC_MOUSEUP3_SCROLLBAR_SLIDER;
+			if (where == SCROLLBAR_DOWN)
+				key = KEYC_MOUSEUP3_SCROLLBAR_DOWN;
 			if (where == BORDER)
 				key = KEYC_MOUSEUP3_BORDER;
 			break;
@@ -1186,6 +1350,12 @@ have_event:
 				key = KEYC_MOUSEUP6_STATUS_RIGHT;
 			if (where == STATUS_DEFAULT)
 				key = KEYC_MOUSEUP6_STATUS_DEFAULT;
+			if (where == SCROLLBAR_UP)
+				key = KEYC_MOUSEUP6_SCROLLBAR_UP;
+			if (where == SCROLLBAR_SLIDER)
+				key = KEYC_MOUSEUP6_SCROLLBAR_SLIDER;
+			if (where == SCROLLBAR_DOWN)
+				key = KEYC_MOUSEUP6_SCROLLBAR_DOWN;
 			if (where == BORDER)
 				key = KEYC_MOUSEUP6_BORDER;
 			break;
@@ -1200,6 +1370,12 @@ have_event:
 				key = KEYC_MOUSEUP7_STATUS_RIGHT;
 			if (where == STATUS_DEFAULT)
 				key = KEYC_MOUSEUP7_STATUS_DEFAULT;
+			if (where == SCROLLBAR_UP)
+				key = KEYC_MOUSEUP7_SCROLLBAR_UP;
+			if (where == SCROLLBAR_SLIDER)
+				key = KEYC_MOUSEUP7_SCROLLBAR_SLIDER;
+			if (where == SCROLLBAR_DOWN)
+				key = KEYC_MOUSEUP7_SCROLLBAR_DOWN;
 			if (where == BORDER)
 				key = KEYC_MOUSEUP7_BORDER;
 			break;
@@ -1214,6 +1390,12 @@ have_event:
 				key = KEYC_MOUSEUP8_STATUS_RIGHT;
 			if (where == STATUS_DEFAULT)
 				key = KEYC_MOUSEUP8_STATUS_DEFAULT;
+			if (where == SCROLLBAR_UP)
+				key = KEYC_MOUSEUP8_SCROLLBAR_UP;
+			if (where == SCROLLBAR_SLIDER)
+				key = KEYC_MOUSEUP8_SCROLLBAR_SLIDER;
+			if (where == SCROLLBAR_DOWN)
+				key = KEYC_MOUSEUP8_SCROLLBAR_DOWN;
 			if (where == BORDER)
 				key = KEYC_MOUSEUP8_BORDER;
 			break;
@@ -1228,6 +1410,12 @@ have_event:
 				key = KEYC_MOUSEUP9_STATUS_RIGHT;
 			if (where == STATUS_DEFAULT)
 				key = KEYC_MOUSEUP9_STATUS_DEFAULT;
+			if (where == SCROLLBAR_UP)
+				key = KEYC_MOUSEUP9_SCROLLBAR_UP;
+			if (where == SCROLLBAR_SLIDER)
+				key = KEYC_MOUSEUP9_SCROLLBAR_SLIDER;
+			if (where == SCROLLBAR_DOWN)
+				key = KEYC_MOUSEUP9_SCROLLBAR_DOWN;
 			if (where == BORDER)
 				key = KEYC_MOUSEUP9_BORDER;
 			break;
@@ -1241,7 +1429,13 @@ have_event:
 			if (where == STATUS_RIGHT)
 				key = KEYC_MOUSEUP1_STATUS_RIGHT;
 			if (where == STATUS_DEFAULT)
-				key = KEYC_MOUSEUP1_STATUS_DEFAULT;
+				key = KEYC_MOUSEUP10_STATUS_DEFAULT;
+			if (where == SCROLLBAR_UP)
+				key = KEYC_MOUSEUP10_SCROLLBAR_UP;
+			if (where == SCROLLBAR_SLIDER)
+				key = KEYC_MOUSEUP10_SCROLLBAR_SLIDER;
+			if (where == SCROLLBAR_DOWN)
+				key = KEYC_MOUSEUP1_SCROLLBAR_DOWN;
 			if (where == BORDER)
 				key = KEYC_MOUSEUP1_BORDER;
 			break;
@@ -1256,6 +1450,12 @@ have_event:
 				key = KEYC_MOUSEUP11_STATUS_RIGHT;
 			if (where == STATUS_DEFAULT)
 				key = KEYC_MOUSEUP11_STATUS_DEFAULT;
+			if (where == SCROLLBAR_UP)
+				key = KEYC_MOUSEUP11_SCROLLBAR_UP;
+			if (where == SCROLLBAR_SLIDER)
+				key = KEYC_MOUSEUP11_SCROLLBAR_SLIDER;
+			if (where == SCROLLBAR_DOWN)
+				key = KEYC_MOUSEUP11_SCROLLBAR_DOWN;
 			if (where == BORDER)
 				key = KEYC_MOUSEUP11_BORDER;
 			break;
@@ -1274,6 +1474,12 @@ have_event:
 				key = KEYC_MOUSEDOWN1_STATUS_RIGHT;
 			if (where == STATUS_DEFAULT)
 				key = KEYC_MOUSEDOWN1_STATUS_DEFAULT;
+			if (where == SCROLLBAR_UP)
+				key = KEYC_MOUSEDOWN1_SCROLLBAR_UP;
+			if (where == SCROLLBAR_SLIDER)
+				key = KEYC_MOUSEDOWN1_SCROLLBAR_SLIDER;
+			if (where == SCROLLBAR_DOWN)
+				key = KEYC_MOUSEDOWN1_SCROLLBAR_DOWN;
 			if (where == BORDER)
 				key = KEYC_MOUSEDOWN1_BORDER;
 			break;
@@ -1288,6 +1494,12 @@ have_event:
 				key = KEYC_MOUSEDOWN2_STATUS_RIGHT;
 			if (where == STATUS_DEFAULT)
 				key = KEYC_MOUSEDOWN2_STATUS_DEFAULT;
+			if (where == SCROLLBAR_UP)
+				key = KEYC_MOUSEDOWN2_SCROLLBAR_UP;
+			if (where == SCROLLBAR_SLIDER)
+				key = KEYC_MOUSEDOWN2_SCROLLBAR_SLIDER;
+			if (where == SCROLLBAR_DOWN)
+				key = KEYC_MOUSEDOWN2_SCROLLBAR_DOWN;
 			if (where == BORDER)
 				key = KEYC_MOUSEDOWN2_BORDER;
 			break;
@@ -1302,6 +1514,12 @@ have_event:
 				key = KEYC_MOUSEDOWN3_STATUS_RIGHT;
 			if (where == STATUS_DEFAULT)
 				key = KEYC_MOUSEDOWN3_STATUS_DEFAULT;
+			if (where == SCROLLBAR_UP)
+				key = KEYC_MOUSEDOWN3_SCROLLBAR_UP;
+			if (where == SCROLLBAR_SLIDER)
+				key = KEYC_MOUSEDOWN3_SCROLLBAR_SLIDER;
+			if (where == SCROLLBAR_DOWN)
+				key = KEYC_MOUSEDOWN3_SCROLLBAR_DOWN;
 			if (where == BORDER)
 				key = KEYC_MOUSEDOWN3_BORDER;
 			break;
@@ -1316,6 +1534,12 @@ have_event:
 				key = KEYC_MOUSEDOWN6_STATUS_RIGHT;
 			if (where == STATUS_DEFAULT)
 				key = KEYC_MOUSEDOWN6_STATUS_DEFAULT;
+			if (where == SCROLLBAR_UP)
+				key = KEYC_MOUSEDOWN6_SCROLLBAR_UP;
+			if (where == SCROLLBAR_SLIDER)
+				key = KEYC_MOUSEDOWN6_SCROLLBAR_SLIDER;
+			if (where == SCROLLBAR_DOWN)
+				key = KEYC_MOUSEDOWN6_SCROLLBAR_DOWN;
 			if (where == BORDER)
 				key = KEYC_MOUSEDOWN6_BORDER;
 			break;
@@ -1330,6 +1554,12 @@ have_event:
 				key = KEYC_MOUSEDOWN7_STATUS_RIGHT;
 			if (where == STATUS_DEFAULT)
 				key = KEYC_MOUSEDOWN7_STATUS_DEFAULT;
+			if (where == SCROLLBAR_UP)
+				key = KEYC_MOUSEDOWN7_SCROLLBAR_UP;
+			if (where == SCROLLBAR_SLIDER)
+				key = KEYC_MOUSEDOWN7_SCROLLBAR_SLIDER;
+			if (where == SCROLLBAR_DOWN)
+				key = KEYC_MOUSEDOWN7_SCROLLBAR_DOWN;
 			if (where == BORDER)
 				key = KEYC_MOUSEDOWN7_BORDER;
 			break;
@@ -1344,6 +1574,12 @@ have_event:
 				key = KEYC_MOUSEDOWN8_STATUS_RIGHT;
 			if (where == STATUS_DEFAULT)
 				key = KEYC_MOUSEDOWN8_STATUS_DEFAULT;
+			if (where == SCROLLBAR_UP)
+				key = KEYC_MOUSEDOWN8_SCROLLBAR_UP;
+			if (where == SCROLLBAR_SLIDER)
+				key = KEYC_MOUSEDOWN8_SCROLLBAR_SLIDER;
+			if (where == SCROLLBAR_DOWN)
+				key = KEYC_MOUSEDOWN8_SCROLLBAR_DOWN;
 			if (where == BORDER)
 				key = KEYC_MOUSEDOWN8_BORDER;
 			break;
@@ -1358,6 +1594,12 @@ have_event:
 				key = KEYC_MOUSEDOWN9_STATUS_RIGHT;
 			if (where == STATUS_DEFAULT)
 				key = KEYC_MOUSEDOWN9_STATUS_DEFAULT;
+			if (where == SCROLLBAR_UP)
+				key = KEYC_MOUSEDOWN9_SCROLLBAR_UP;
+			if (where == SCROLLBAR_SLIDER)
+				key = KEYC_MOUSEDOWN9_SCROLLBAR_SLIDER;
+			if (where == SCROLLBAR_DOWN)
+				key = KEYC_MOUSEDOWN9_SCROLLBAR_DOWN;
 			if (where == BORDER)
 				key = KEYC_MOUSEDOWN9_BORDER;
 			break;
@@ -1372,6 +1614,12 @@ have_event:
 				key = KEYC_MOUSEDOWN10_STATUS_RIGHT;
 			if (where == STATUS_DEFAULT)
 				key = KEYC_MOUSEDOWN10_STATUS_DEFAULT;
+			if (where == SCROLLBAR_UP)
+				key = KEYC_MOUSEDOWN10_SCROLLBAR_UP;
+			if (where == SCROLLBAR_SLIDER)
+				key = KEYC_MOUSEDOWN10_SCROLLBAR_SLIDER;
+			if (where == SCROLLBAR_DOWN)
+				key = KEYC_MOUSEDOWN10_SCROLLBAR_DOWN;
 			if (where == BORDER)
 				key = KEYC_MOUSEDOWN10_BORDER;
 			break;
@@ -1386,6 +1634,12 @@ have_event:
 				key = KEYC_MOUSEDOWN11_STATUS_RIGHT;
 			if (where == STATUS_DEFAULT)
 				key = KEYC_MOUSEDOWN11_STATUS_DEFAULT;
+			if (where == SCROLLBAR_UP)
+				key = KEYC_MOUSEDOWN11_SCROLLBAR_UP;
+			if (where == SCROLLBAR_SLIDER)
+				key = KEYC_MOUSEDOWN11_SCROLLBAR_SLIDER;
+			if (where == SCROLLBAR_DOWN)
+				key = KEYC_MOUSEDOWN11_SCROLLBAR_DOWN;
 			if (where == BORDER)
 				key = KEYC_MOUSEDOWN11_BORDER;
 			break;
@@ -1404,6 +1658,12 @@ have_event:
 				key = KEYC_SECONDCLICK1_STATUS_RIGHT;
 			if (where == STATUS_DEFAULT)
 				key = KEYC_SECONDCLICK1_STATUS_DEFAULT;
+			if (where == SCROLLBAR_UP)
+				key = KEYC_SECONDCLICK1_SCROLLBAR_UP;
+			if (where == SCROLLBAR_SLIDER)
+				key = KEYC_SECONDCLICK1_SCROLLBAR_SLIDER;
+			if (where == SCROLLBAR_DOWN)
+				key = KEYC_SECONDCLICK1_SCROLLBAR_DOWN;
 			if (where == BORDER)
 				key = KEYC_SECONDCLICK1_BORDER;
 			break;
@@ -1418,6 +1678,12 @@ have_event:
 				key = KEYC_SECONDCLICK2_STATUS_RIGHT;
 			if (where == STATUS_DEFAULT)
 				key = KEYC_SECONDCLICK2_STATUS_DEFAULT;
+			if (where == SCROLLBAR_UP)
+				key = KEYC_SECONDCLICK2_SCROLLBAR_UP;
+			if (where == SCROLLBAR_SLIDER)
+				key = KEYC_SECONDCLICK2_SCROLLBAR_SLIDER;
+			if (where == SCROLLBAR_DOWN)
+				key = KEYC_SECONDCLICK2_SCROLLBAR_DOWN;
 			if (where == BORDER)
 				key = KEYC_SECONDCLICK2_BORDER;
 			break;
@@ -1432,6 +1698,12 @@ have_event:
 				key = KEYC_SECONDCLICK3_STATUS_RIGHT;
 			if (where == STATUS_DEFAULT)
 				key = KEYC_SECONDCLICK3_STATUS_DEFAULT;
+			if (where == SCROLLBAR_UP)
+				key = KEYC_SECONDCLICK3_SCROLLBAR_UP;
+			if (where == SCROLLBAR_SLIDER)
+				key = KEYC_SECONDCLICK3_SCROLLBAR_SLIDER;
+			if (where == SCROLLBAR_DOWN)
+				key = KEYC_SECONDCLICK3_SCROLLBAR_DOWN;
 			if (where == BORDER)
 				key = KEYC_SECONDCLICK3_BORDER;
 			break;
@@ -1446,6 +1718,12 @@ have_event:
 				key = KEYC_SECONDCLICK6_STATUS_RIGHT;
 			if (where == STATUS_DEFAULT)
 				key = KEYC_SECONDCLICK6_STATUS_DEFAULT;
+			if (where == SCROLLBAR_UP)
+				key = KEYC_SECONDCLICK6_SCROLLBAR_UP;
+			if (where == SCROLLBAR_SLIDER)
+				key = KEYC_SECONDCLICK6_SCROLLBAR_SLIDER;
+			if (where == SCROLLBAR_DOWN)
+				key = KEYC_SECONDCLICK6_SCROLLBAR_DOWN;
 			if (where == BORDER)
 				key = KEYC_SECONDCLICK6_BORDER;
 			break;
@@ -1460,6 +1738,12 @@ have_event:
 				key = KEYC_SECONDCLICK7_STATUS_RIGHT;
 			if (where == STATUS_DEFAULT)
 				key = KEYC_SECONDCLICK7_STATUS_DEFAULT;
+			if (where == SCROLLBAR_UP)
+				key = KEYC_SECONDCLICK7_SCROLLBAR_UP;
+			if (where == SCROLLBAR_SLIDER)
+				key = KEYC_SECONDCLICK7_SCROLLBAR_SLIDER;
+			if (where == SCROLLBAR_DOWN)
+				key = KEYC_SECONDCLICK7_SCROLLBAR_DOWN;
 			if (where == BORDER)
 				key = KEYC_SECONDCLICK7_BORDER;
 			break;
@@ -1474,6 +1758,12 @@ have_event:
 				key = KEYC_SECONDCLICK8_STATUS_RIGHT;
 			if (where == STATUS_DEFAULT)
 				key = KEYC_SECONDCLICK8_STATUS_DEFAULT;
+			if (where == SCROLLBAR_UP)
+				key = KEYC_SECONDCLICK8_SCROLLBAR_UP;
+			if (where == SCROLLBAR_SLIDER)
+				key = KEYC_SECONDCLICK8_SCROLLBAR_SLIDER;
+			if (where == SCROLLBAR_DOWN)
+				key = KEYC_SECONDCLICK8_SCROLLBAR_DOWN;
 			if (where == BORDER)
 				key = KEYC_SECONDCLICK8_BORDER;
 			break;
@@ -1488,6 +1778,12 @@ have_event:
 				key = KEYC_SECONDCLICK9_STATUS_RIGHT;
 			if (where == STATUS_DEFAULT)
 				key = KEYC_SECONDCLICK9_STATUS_DEFAULT;
+			if (where == SCROLLBAR_UP)
+				key = KEYC_SECONDCLICK9_SCROLLBAR_UP;
+			if (where == SCROLLBAR_SLIDER)
+				key = KEYC_SECONDCLICK9_SCROLLBAR_SLIDER;
+			if (where == SCROLLBAR_DOWN)
+				key = KEYC_SECONDCLICK9_SCROLLBAR_DOWN;
 			if (where == BORDER)
 				key = KEYC_SECONDCLICK9_BORDER;
 			break;
@@ -1502,6 +1798,12 @@ have_event:
 				key = KEYC_SECONDCLICK10_STATUS_RIGHT;
 			if (where == STATUS_DEFAULT)
 				key = KEYC_SECONDCLICK10_STATUS_DEFAULT;
+			if (where == SCROLLBAR_UP)
+				key = KEYC_SECONDCLICK10_SCROLLBAR_UP;
+			if (where == SCROLLBAR_SLIDER)
+				key = KEYC_SECONDCLICK10_SCROLLBAR_SLIDER;
+			if (where == SCROLLBAR_DOWN)
+				key = KEYC_SECONDCLICK10_SCROLLBAR_DOWN;
 			if (where == BORDER)
 				key = KEYC_SECONDCLICK10_BORDER;
 			break;
@@ -1516,6 +1818,12 @@ have_event:
 				key = KEYC_SECONDCLICK11_STATUS_RIGHT;
 			if (where == STATUS_DEFAULT)
 				key = KEYC_SECONDCLICK11_STATUS_DEFAULT;
+			if (where == SCROLLBAR_UP)
+				key = KEYC_SECONDCLICK11_SCROLLBAR_UP;
+			if (where == SCROLLBAR_SLIDER)
+				key = KEYC_SECONDCLICK11_SCROLLBAR_SLIDER;
+			if (where == SCROLLBAR_DOWN)
+				key = KEYC_SECONDCLICK11_SCROLLBAR_DOWN;
 			if (where == BORDER)
 				key = KEYC_SECONDCLICK11_BORDER;
 			break;
@@ -1534,6 +1842,12 @@ have_event:
 				key = KEYC_DOUBLECLICK1_STATUS_RIGHT;
 			if (where == STATUS_DEFAULT)
 				key = KEYC_DOUBLECLICK1_STATUS_DEFAULT;
+			if (where == SCROLLBAR_UP)
+				key = KEYC_DOUBLECLICK1_SCROLLBAR_UP;
+			if (where == SCROLLBAR_SLIDER)
+				key = KEYC_DOUBLECLICK1_SCROLLBAR_SLIDER;
+			if (where == SCROLLBAR_DOWN)
+				key = KEYC_DOUBLECLICK1_SCROLLBAR_DOWN;
 			if (where == BORDER)
 				key = KEYC_DOUBLECLICK1_BORDER;
 			break;
@@ -1548,6 +1862,12 @@ have_event:
 				key = KEYC_DOUBLECLICK2_STATUS_RIGHT;
 			if (where == STATUS_DEFAULT)
 				key = KEYC_DOUBLECLICK2_STATUS_DEFAULT;
+			if (where == SCROLLBAR_UP)
+				key = KEYC_DOUBLECLICK2_SCROLLBAR_UP;
+			if (where == SCROLLBAR_SLIDER)
+				key = KEYC_DOUBLECLICK2_SCROLLBAR_SLIDER;
+			if (where == SCROLLBAR_DOWN)
+				key = KEYC_DOUBLECLICK2_SCROLLBAR_DOWN;
 			if (where == BORDER)
 				key = KEYC_DOUBLECLICK2_BORDER;
 			break;
@@ -1562,6 +1882,12 @@ have_event:
 				key = KEYC_DOUBLECLICK3_STATUS_RIGHT;
 			if (where == STATUS_DEFAULT)
 				key = KEYC_DOUBLECLICK3_STATUS_DEFAULT;
+			if (where == SCROLLBAR_UP)
+				key = KEYC_DOUBLECLICK3_SCROLLBAR_UP;
+			if (where == SCROLLBAR_SLIDER)
+				key = KEYC_DOUBLECLICK3_SCROLLBAR_SLIDER;
+			if (where == SCROLLBAR_DOWN)
+				key = KEYC_DOUBLECLICK3_SCROLLBAR_DOWN;
 			if (where == BORDER)
 				key = KEYC_DOUBLECLICK3_BORDER;
 			break;
@@ -1576,6 +1902,12 @@ have_event:
 				key = KEYC_DOUBLECLICK6_STATUS_RIGHT;
 			if (where == STATUS_DEFAULT)
 				key = KEYC_DOUBLECLICK6_STATUS_DEFAULT;
+			if (where == SCROLLBAR_UP)
+				key = KEYC_DOUBLECLICK6_SCROLLBAR_UP;
+			if (where == SCROLLBAR_SLIDER)
+				key = KEYC_DOUBLECLICK6_SCROLLBAR_SLIDER;
+			if (where == SCROLLBAR_DOWN)
+				key = KEYC_DOUBLECLICK6_SCROLLBAR_DOWN;
 			if (where == BORDER)
 				key = KEYC_DOUBLECLICK6_BORDER;
 			break;
@@ -1590,6 +1922,12 @@ have_event:
 				key = KEYC_DOUBLECLICK7_STATUS_RIGHT;
 			if (where == STATUS_DEFAULT)
 				key = KEYC_DOUBLECLICK7_STATUS_DEFAULT;
+			if (where == SCROLLBAR_UP)
+				key = KEYC_DOUBLECLICK7_SCROLLBAR_UP;
+			if (where == SCROLLBAR_SLIDER)
+				key = KEYC_DOUBLECLICK7_SCROLLBAR_SLIDER;
+			if (where == SCROLLBAR_DOWN)
+				key = KEYC_DOUBLECLICK7_SCROLLBAR_DOWN;
 			if (where == BORDER)
 				key = KEYC_DOUBLECLICK7_BORDER;
 			break;
@@ -1604,6 +1942,12 @@ have_event:
 				key = KEYC_DOUBLECLICK8_STATUS_RIGHT;
 			if (where == STATUS_DEFAULT)
 				key = KEYC_DOUBLECLICK8_STATUS_DEFAULT;
+			if (where == SCROLLBAR_UP)
+				key = KEYC_DOUBLECLICK8_SCROLLBAR_UP;
+			if (where == SCROLLBAR_SLIDER)
+				key = KEYC_DOUBLECLICK8_SCROLLBAR_SLIDER;
+			if (where == SCROLLBAR_DOWN)
+				key = KEYC_DOUBLECLICK8_SCROLLBAR_DOWN;
 			if (where == BORDER)
 				key = KEYC_DOUBLECLICK8_BORDER;
 			break;
@@ -1618,6 +1962,12 @@ have_event:
 				key = KEYC_DOUBLECLICK9_STATUS_RIGHT;
 			if (where == STATUS_DEFAULT)
 				key = KEYC_DOUBLECLICK9_STATUS_DEFAULT;
+			if (where == SCROLLBAR_UP)
+				key = KEYC_DOUBLECLICK9_SCROLLBAR_UP;
+			if (where == SCROLLBAR_SLIDER)
+				key = KEYC_DOUBLECLICK9_SCROLLBAR_SLIDER;
+			if (where == SCROLLBAR_DOWN)
+				key = KEYC_DOUBLECLICK9_SCROLLBAR_DOWN;
 			if (where == BORDER)
 				key = KEYC_DOUBLECLICK9_BORDER;
 			break;
@@ -1632,6 +1982,12 @@ have_event:
 				key = KEYC_DOUBLECLICK10_STATUS_RIGHT;
 			if (where == STATUS_DEFAULT)
 				key = KEYC_DOUBLECLICK10_STATUS_DEFAULT;
+			if (where == SCROLLBAR_UP)
+				key = KEYC_DOUBLECLICK10_SCROLLBAR_UP;
+			if (where == SCROLLBAR_SLIDER)
+				key = KEYC_DOUBLECLICK10_SCROLLBAR_SLIDER;
+			if (where == SCROLLBAR_DOWN)
+				key = KEYC_DOUBLECLICK10_SCROLLBAR_DOWN;
 			if (where == BORDER)
 				key = KEYC_DOUBLECLICK10_BORDER;
 			break;
@@ -1646,6 +2002,12 @@ have_event:
 				key = KEYC_DOUBLECLICK11_STATUS_RIGHT;
 			if (where == STATUS_DEFAULT)
 				key = KEYC_DOUBLECLICK11_STATUS_DEFAULT;
+			if (where == SCROLLBAR_UP)
+				key = KEYC_DOUBLECLICK11_SCROLLBAR_UP;
+			if (where == SCROLLBAR_SLIDER)
+				key = KEYC_DOUBLECLICK11_SCROLLBAR_SLIDER;
+			if (where == SCROLLBAR_DOWN)
+				key = KEYC_DOUBLECLICK11_SCROLLBAR_DOWN;
 			if (where == BORDER)
 				key = KEYC_DOUBLECLICK11_BORDER;
 			break;
@@ -1664,6 +2026,12 @@ have_event:
 				key = KEYC_TRIPLECLICK1_STATUS_RIGHT;
 			if (where == STATUS_DEFAULT)
 				key = KEYC_TRIPLECLICK1_STATUS_DEFAULT;
+			if (where == SCROLLBAR_UP)
+				key = KEYC_TRIPLECLICK1_SCROLLBAR_UP;
+			if (where == SCROLLBAR_SLIDER)
+				key = KEYC_TRIPLECLICK1_SCROLLBAR_SLIDER;
+			if (where == SCROLLBAR_DOWN)
+				key = KEYC_TRIPLECLICK1_SCROLLBAR_DOWN;
 			if (where == BORDER)
 				key = KEYC_TRIPLECLICK1_BORDER;
 			break;
@@ -1678,6 +2046,12 @@ have_event:
 				key = KEYC_TRIPLECLICK2_STATUS_RIGHT;
 			if (where == STATUS_DEFAULT)
 				key = KEYC_TRIPLECLICK2_STATUS_DEFAULT;
+			if (where == SCROLLBAR_UP)
+				key = KEYC_TRIPLECLICK2_SCROLLBAR_UP;
+			if (where == SCROLLBAR_SLIDER)
+				key = KEYC_TRIPLECLICK2_SCROLLBAR_SLIDER;
+			if (where == SCROLLBAR_DOWN)
+				key = KEYC_TRIPLECLICK2_SCROLLBAR_DOWN;
 			if (where == BORDER)
 				key = KEYC_TRIPLECLICK2_BORDER;
 			break;
@@ -1692,6 +2066,12 @@ have_event:
 				key = KEYC_TRIPLECLICK3_STATUS_RIGHT;
 			if (where == STATUS_DEFAULT)
 				key = KEYC_TRIPLECLICK3_STATUS_DEFAULT;
+			if (where == SCROLLBAR_UP)
+				key = KEYC_TRIPLECLICK3_SCROLLBAR_UP;
+			if (where == SCROLLBAR_SLIDER)
+				key = KEYC_TRIPLECLICK3_SCROLLBAR_SLIDER;
+			if (where == SCROLLBAR_DOWN)
+				key = KEYC_TRIPLECLICK3_SCROLLBAR_DOWN;
 			if (where == BORDER)
 				key = KEYC_TRIPLECLICK3_BORDER;
 			break;
@@ -1706,6 +2086,12 @@ have_event:
 				key = KEYC_TRIPLECLICK6_STATUS_RIGHT;
 			if (where == STATUS_DEFAULT)
 				key = KEYC_TRIPLECLICK6_STATUS_DEFAULT;
+			if (where == SCROLLBAR_UP)
+				key = KEYC_TRIPLECLICK6_SCROLLBAR_UP;
+			if (where == SCROLLBAR_SLIDER)
+				key = KEYC_TRIPLECLICK6_SCROLLBAR_SLIDER;
+			if (where == SCROLLBAR_DOWN)
+				key = KEYC_TRIPLECLICK6_SCROLLBAR_DOWN;
 			if (where == BORDER)
 				key = KEYC_TRIPLECLICK6_BORDER;
 			break;
@@ -1720,6 +2106,12 @@ have_event:
 				key = KEYC_TRIPLECLICK7_STATUS_RIGHT;
 			if (where == STATUS_DEFAULT)
 				key = KEYC_TRIPLECLICK7_STATUS_DEFAULT;
+			if (where == SCROLLBAR_UP)
+				key = KEYC_TRIPLECLICK7_SCROLLBAR_UP;
+			if (where == SCROLLBAR_SLIDER)
+				key = KEYC_TRIPLECLICK7_SCROLLBAR_SLIDER;
+			if (where == SCROLLBAR_DOWN)
+				key = KEYC_TRIPLECLICK7_SCROLLBAR_DOWN;
 			if (where == BORDER)
 				key = KEYC_TRIPLECLICK7_BORDER;
 			break;
@@ -1734,6 +2126,12 @@ have_event:
 				key = KEYC_TRIPLECLICK8_STATUS_RIGHT;
 			if (where == STATUS_DEFAULT)
 				key = KEYC_TRIPLECLICK8_STATUS_DEFAULT;
+			if (where == SCROLLBAR_UP)
+				key = KEYC_TRIPLECLICK8_SCROLLBAR_UP;
+			if (where == SCROLLBAR_SLIDER)
+				key = KEYC_TRIPLECLICK8_SCROLLBAR_SLIDER;
+			if (where == SCROLLBAR_DOWN)
+				key = KEYC_TRIPLECLICK8_SCROLLBAR_DOWN;
 			if (where == BORDER)
 				key = KEYC_TRIPLECLICK8_BORDER;
 			break;
@@ -1748,6 +2146,12 @@ have_event:
 				key = KEYC_TRIPLECLICK9_STATUS_RIGHT;
 			if (where == STATUS_DEFAULT)
 				key = KEYC_TRIPLECLICK9_STATUS_DEFAULT;
+			if (where == SCROLLBAR_UP)
+				key = KEYC_TRIPLECLICK9_SCROLLBAR_UP;
+			if (where == SCROLLBAR_SLIDER)
+				key = KEYC_TRIPLECLICK9_SCROLLBAR_SLIDER;
+			if (where == SCROLLBAR_DOWN)
+				key = KEYC_TRIPLECLICK9_SCROLLBAR_DOWN;
 			if (where == BORDER)
 				key = KEYC_TRIPLECLICK9_BORDER;
 			break;
@@ -1762,6 +2166,12 @@ have_event:
 				key = KEYC_TRIPLECLICK10_STATUS_RIGHT;
 			if (where == STATUS_DEFAULT)
 				key = KEYC_TRIPLECLICK10_STATUS_DEFAULT;
+			if (where == SCROLLBAR_UP)
+				key = KEYC_TRIPLECLICK10_SCROLLBAR_UP;
+			if (where == SCROLLBAR_SLIDER)
+				key = KEYC_TRIPLECLICK10_SCROLLBAR_SLIDER;
+			if (where == SCROLLBAR_DOWN)
+				key = KEYC_TRIPLECLICK10_SCROLLBAR_DOWN;
 			if (where == BORDER)
 				key = KEYC_TRIPLECLICK10_BORDER;
 			break;
@@ -1776,6 +2186,12 @@ have_event:
 				key = KEYC_TRIPLECLICK11_STATUS_RIGHT;
 			if (where == STATUS_DEFAULT)
 				key = KEYC_TRIPLECLICK11_STATUS_DEFAULT;
+			if (where == SCROLLBAR_UP)
+				key = KEYC_TRIPLECLICK11_SCROLLBAR_UP;
+			if (where == SCROLLBAR_SLIDER)
+				key = KEYC_TRIPLECLICK11_SCROLLBAR_SLIDER;
+			if (where == SCROLLBAR_DOWN)
+				key = KEYC_TRIPLECLICK11_SCROLLBAR_DOWN;
 			if (where == BORDER)
 				key = KEYC_TRIPLECLICK11_BORDER;
 			break;
diff --git a/usr.bin/tmux/tmux.1 b/usr.bin/tmux/tmux.1
index 612798cef93..664454095ef 100644
--- a/usr.bin/tmux/tmux.1
+++ b/usr.bin/tmux/tmux.1
@@ -1,4 +1,4 @@
-.\" $OpenBSD: tmux.1,v 1.970 2024/11/11 08:41:05 nicm Exp $
+.\" $OpenBSD: tmux.1,v 1.971 2024/11/12 09:32:56 nicm Exp $
 .\"
 .\" Copyright (c) 2007 Nicholas Marriott <nicholas.marriott@gmail.com>
 .\"
@@ -14,7 +14,7 @@
 .\" IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
 .\" OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 .\"
-.Dd $Mdocdate: November 11 2024 $
+.Dd $Mdocdate: November 12 2024 $
 .Dt TMUX 1
 .Os
 .Sh NAME
@@ -2400,22 +2400,31 @@ The synopsis for the
 command is:
 .Bl -tag -width Ds
 .It Xo Ic copy-mode
-.Op Fl deHMqu
+.Op Fl deHMqSu
 .Op Fl s Ar src-pane
 .Op Fl t Ar target-pane
 .Xc
 Enter copy mode.
+.Pp
 .Fl u
-also scrolls one page up after entering and
+enters copy mode and scrolls one page up and
 .Fl d
-one page down if already in copy mode.
-.Fl M
-begins a mouse drag (only valid if bound to a mouse key binding, see
-.Sx MOUSE SUPPORT ) .
+one page down.
 .Fl H
 hides the position indicator in the top right.
 .Fl q
 cancels copy mode and any other modes.
+.Pp
+.Fl M
+begins a mouse drag (only valid if bound to a mouse key binding, see
+.Sx MOUSE SUPPORT ) .
+.Fl S
+scrolls when bound to a mouse drag event; for example,
+.Ic copy-mode -Se
+is bound to
+.Ar MouseDrag1ScrollbarSlider
+by default.
+.Pp
 .Fl s
 copies from
 .Ar src-pane
@@ -5441,6 +5450,9 @@ and a location suffix, one of the following:
 .It Li "StatusLeft" Ta "the left part of the status line"
 .It Li "StatusRight" Ta "the right part of the status line"
 .It Li "StatusDefault" Ta "any other part of the status line"
+.It Li "ScrollbarSlider" Ta "the scrollbar slider"
+.It Li "ScrollbarUp" Ta "above the scrollbar slider"
+.It Li "ScrollbarDown" Ta "below the scrollbar slider"
 .El
 .Pp
 The following mouse events are available:
diff --git a/usr.bin/tmux/tmux.h b/usr.bin/tmux/tmux.h
index a46ba92b4f2..f098f452293 100644
--- a/usr.bin/tmux/tmux.h
+++ b/usr.bin/tmux/tmux.h
@@ -1,4 +1,4 @@
-/* $OpenBSD: tmux.h,v 1.1239 2024/11/11 08:41:05 nicm Exp $ */
+/* $OpenBSD: tmux.h,v 1.1240 2024/11/12 09:32:56 nicm Exp $ */
 
 /*
  * Copyright (c) 2007 Nicholas Marriott <nicholas.marriott@gmail.com>
@@ -169,19 +169,25 @@ struct winlink;
 #define KEYC_CLICK_TIMEOUT 300
 
 /* Mouse key codes. */
-#define KEYC_MOUSE_KEY(name)					\
-	KEYC_ ## name ## _PANE,					\
-	KEYC_ ## name ## _STATUS,				\
-	KEYC_ ## name ## _STATUS_LEFT,				\
-	KEYC_ ## name ## _STATUS_RIGHT,				\
-	KEYC_ ## name ## _STATUS_DEFAULT,			\
+#define KEYC_MOUSE_KEY(name)		    \
+	KEYC_ ## name ## _PANE,		    \
+	KEYC_ ## name ## _STATUS,	    \
+	KEYC_ ## name ## _STATUS_LEFT,	    \
+	KEYC_ ## name ## _STATUS_RIGHT,	    \
+	KEYC_ ## name ## _STATUS_DEFAULT,   \
+	KEYC_ ## name ## _SCROLLBAR_UP,	    \
+	KEYC_ ## name ## _SCROLLBAR_SLIDER, \
+	KEYC_ ## name ## _SCROLLBAR_DOWN,   \
 	KEYC_ ## name ## _BORDER
-#define KEYC_MOUSE_STRING(name, s)				\
-	{ #s "Pane", KEYC_ ## name ## _PANE },			\
-	{ #s "Status", KEYC_ ## name ## _STATUS },		\
-	{ #s "StatusLeft", KEYC_ ## name ## _STATUS_LEFT },	\
-	{ #s "StatusRight", KEYC_ ## name ## _STATUS_RIGHT },	\
-	{ #s "StatusDefault", KEYC_ ## name ## _STATUS_DEFAULT }, \
+#define KEYC_MOUSE_STRING(name, s)				      \
+	{ #s "Pane", KEYC_ ## name ## _PANE },			      \
+	{ #s "Status", KEYC_ ## name ## _STATUS },		      \
+	{ #s "StatusLeft", KEYC_ ## name ## _STATUS_LEFT },	      \
+	{ #s "StatusRight", KEYC_ ## name ## _STATUS_RIGHT },	      \
+	{ #s "StatusDefault", KEYC_ ## name ## _STATUS_DEFAULT },     \
+	{ #s "ScrollbarUp", KEYC_ ## name ## _SCROLLBAR_UP },         \
+	{ #s "ScrollbarSlider", KEYC_ ## name ## _SCROLLBAR_SLIDER }, \
+	{ #s "ScrollbarDown", KEYC_ ## name ## _SCROLLBAR_DOWN },     \
 	{ #s "Border", KEYC_ ## name ## _BORDER }
 
 /*
@@ -1109,6 +1115,9 @@ struct window_pane {
 #define PANE_UNSEENCHANGES 0x2000
 #define PANE_REDRAWSCROLLBAR 0x4000
 
+	u_int		 sb_slider_y;
+	u_int		 sb_slider_h;
+
 	int		 argc;
 	char	       **argv;
 	char		*shell;
@@ -1509,6 +1518,9 @@ struct tty {
 	u_int		 mouse_last_y;
 	u_int		 mouse_last_b;
 	int		 mouse_drag_flag;
+	int		 mouse_scrolling_flag;
+	int		 mouse_slider_mpos;
+
 	void		(*mouse_drag_update)(struct client *,
 			    struct mouse_event *);
 	void		(*mouse_drag_release)(struct client *,
@@ -3266,6 +3278,7 @@ void printflike(3, 4) window_copy_add(struct window_pane *, int, const char *,
 		     ...);
 void printflike(3, 0) window_copy_vadd(struct window_pane *, int, const char *,
 		     va_list);
+void		 window_copy_scroll(struct window_pane *, int, u_int, int);
 void		 window_copy_pageup(struct window_pane *, int);
 void		 window_copy_pagedown(struct window_pane *, int, int);
 void		 window_copy_start_drag(struct client *, struct mouse_event *);
diff --git a/usr.bin/tmux/window-copy.c b/usr.bin/tmux/window-copy.c
index 1a6c6690705..19484ad0cd3 100644
--- a/usr.bin/tmux/window-copy.c
+++ b/usr.bin/tmux/window-copy.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: window-copy.c,v 1.364 2024/11/08 08:51:36 nicm Exp $ */
+/* $OpenBSD: window-copy.c,v 1.365 2024/11/12 09:32:56 nicm Exp $ */
 
 /*
  * Copyright (c) 2007 Nicholas Marriott <nicholas.marriott@gmail.com>
@@ -40,6 +40,8 @@ static void	window_copy_free(struct window_mode_entry *);
 static void	window_copy_resize(struct window_mode_entry *, u_int, u_int);
 static void	window_copy_formats(struct window_mode_entry *,
 		    struct format_tree *);
+static void	window_copy_scroll1(struct window_mode_entry *,
+		    struct window_pane *wp, int, u_int, int);
 static void	window_copy_pageup1(struct window_mode_entry *, int);
 static int	window_copy_pagedown1(struct window_mode_entry *, int, int);
 static void	window_copy_next_paragraph(struct window_mode_entry *);
@@ -599,6 +601,113 @@ window_copy_vadd(struct window_pane *wp, int parse, const char *fmt, va_list ap)
 }
 
 void
+window_copy_scroll(struct window_pane *wp, int sl_mpos, u_int my,
+    int scroll_exit)
+{
+	struct window_mode_entry	*wme = TAILQ_FIRST(&wp->modes);
+
+	if (wme != NULL) {
+		window_set_active_pane(wp->window, wp, 0);
+		window_copy_scroll1(wme, wp, sl_mpos, my, scroll_exit);
+	}
+}
+
+static void
+window_copy_scroll1(struct window_mode_entry *wme, struct window_pane *wp,
+    int sl_mpos, u_int my, int scroll_exit)
+{
+	struct window_copy_mode_data	*data = wme->data;
+	u_int				 ox, oy, px, py, n, offset, size;
+	u_int				 new_offset, slider_y = wp->sb_slider_y;
+	u_int				 slider_height = wp->sb_slider_h;
+	u_int				 sb_height = wp->sy, sb_top = wp->yoff;
+	u_int				 sy = screen_size_y(data->backing);
+	int				 new_slider_y, delta;
+
+	/*
+	 * sl_mpos is where in the slider the user is dragging, mouse is
+	 * dragging this y point relative to top of slider.
+	 */
+	if (my <= sb_top + sl_mpos) {
+		/* Slider banged into top. */
+		new_slider_y = sb_top - wp->yoff;
+	} else if (my - sl_mpos > sb_top + sb_height - slider_height) {
+		/* Slider banged into bottom. */
+		new_slider_y = sb_top - wp->yoff + (sb_height - slider_height);
+	} else {
+		/* Slider is somewhere in the middle. */
+		new_slider_y = my - wp->yoff - sl_mpos + 1;
+	}
+
+	if (TAILQ_FIRST(&wp->modes) == NULL ||
+	    window_copy_get_current_offset(wp, &offset, &size) == 0)
+		return;
+
+	/*
+	 * See screen_redraw_draw_pane_scrollbar - this is the inverse of the
+	 * formula used there.
+	 */
+	new_offset = new_slider_y * ((float)(size + sb_height) / sb_height);
+	delta = (int)offset - new_offset;
+
+	/*
+	 * Move pane view around based on delta relative to the cursor,
+	 * maintaining the selection.
+	 */
+	oy = screen_hsize(data->backing) + data->cy - data->oy;
+	ox = window_copy_find_length(wme, oy);
+
+	if (data->cx != ox) {
+		data->lastcx = data->cx;
+		data->lastsx = ox;
+	}
+	data->cx = data->lastcx;
+
+	if (delta >= 0) {
+		n = (u_int)delta;
+		if (data->oy + n > screen_hsize(data->backing)) {
+			data->oy = screen_hsize(data->backing);
+			if (data->cy < n)
+				data->cy = 0;
+			else
+				data->cy -= n;
+		} else
+			data->oy += n;
+	} else {
+		n = (u_int)-delta;
+		if (data->oy < n) {
+			data->oy = 0;
+			if (data->cy + (n - data->oy) >= sy)
+				data->cy = sy - 1;
+			else
+				data->cy += n - data->oy;
+		} else
+			data->oy -= n;
+	}
+
+	/* Don't also drag tail when dragging a scrollbar, it looks weird. */
+	data->cursordrag = CURSORDRAG_NONE;
+
+	if (data->screen.sel == NULL || !data->rectflag) {
+		py = screen_hsize(data->backing) + data->cy - data->oy;
+		px = window_copy_find_length(wme, py);
+		if ((data->cx >= data->lastsx && data->cx != px) ||
+		    data->cx > px)
+			window_copy_cursor_end_of_line(wme);
+	}
+
+	if (scroll_exit && data->oy == 0) {
+		window_pane_reset_mode(wp);
+		return;
+	}
+
+	if (data->searchmark != NULL && !data->timeout)
+		window_copy_search_marks(wme, NULL, data->searchregex, 1);
+	window_copy_update_selection(wme, 1, 0);
+	window_copy_redraw_screen(wme);
+}
+
+void
 window_copy_pageup(struct window_pane *wp, int half_page)
 {
 	window_copy_pageup1(TAILQ_FIRST(&wp->modes), half_page);