Move lazy resize from the pane to the window, there is no point in resizing the

window unless it is the current window, and if we do and don't resize the pane
until later there are problems if the size changes from A to B then back to A.

resize.c

@@ -61,6 +61,7 @@ resize_window(struct window *w, u_int sx, u_int sy, int xpixel, int ypixel)
 	tty_update_window_offset(w);
 	server_redraw_window(w);
 	notify_window("window-layout-changed", w);
+	w->flags &= ~WINDOW_RESIZE;
 }
 
 static int
@@ -346,16 +347,30 @@ recalculate_size(struct window *w)
 		changed = 0;
 		break;
 	}
+	if (w->flags & WINDOW_RESIZE) {
+		if (changed && w->new_sx == sx && w->new_sy == sy)
+			changed = 0;
+	} else {
 		if (changed && w->sx == sx && w->sy == sy)
 			changed = 0;
+	}
 
 	if (!changed) {
 		tty_update_window_offset(w);
 		return;
 	}
-	log_debug("%s: @%u changed to %u,%u (%ux%u)", __func__, w->id, sx, sy,
+	log_debug("%s: @%u new size %u,%u", __func__, w->id, sx, sy);
-	    xpixel, ypixel);
+	if (type == WINDOW_SIZE_MANUAL)
 		resize_window(w, sx, sy, xpixel, ypixel);
+	else {
+		w->new_sx = sx;
+		w->new_sy = sy;
+		w->new_xpixel = xpixel;
+		w->new_ypixel = ypixel;
+
+		w->flags |= WINDOW_RESIZE;
+		tty_update_window_offset(w);
+	}
 }
 
 void

server-client.c

@@ -31,8 +31,9 @@
 #include "tmux.h"
 
 static void	server_client_free(int, short, void *);
-static void	server_client_check_focus(struct window_pane *);
+static void	server_client_check_pane_focus(struct window_pane *);
-static void	server_client_check_resize(struct window_pane *);
+static void	server_client_check_pane_resize(struct window_pane *);
+static void	server_client_check_window_resize(struct window *);
 static key_code	server_client_check_mouse(struct client *, struct key_event *);
 static void	server_client_repeat_timer(int, short, void *);
 static void	server_client_click_timer(int, short, void *);
@@ -1339,10 +1340,13 @@ server_client_loop(void)
 	struct client		*c;
 	struct window		*w;
 	struct window_pane	*wp;
-	struct winlink		*wl;
+	int			 focus;
-	struct session		*s;
-	int			 focus, attached, resize;
 
+	/* Check for window resize. This is done before redrawing. */
+	RB_FOREACH(w, windows, &windows)
+		server_client_check_window_resize(w);
+
+	/* Check clients. */
 	TAILQ_FOREACH(c, &clients, entry) {
 		server_client_check_exit(c);
 		if (c->session != NULL) {
@@ -1354,34 +1358,14 @@ server_client_loop(void)
 	/*
 	 * Any windows will have been redrawn as part of clients, so clear
 	 * their flags now. Also check pane focus and resize.
-	 *
-	 * As an optimization, panes in windows that are in an attached session
-	 * but not the current window are not resized (this reduces the amount
-	 * of work needed when, for example, resizing an X terminal a
-	 * lot). Windows in no attached session are resized immediately since
-	 * that is likely to have come from a command like split-window and be
-	 * what the user wanted.
 	 */
 	focus = options_get_number(global_options, "focus-events");
 	RB_FOREACH(w, windows, &windows) {
-		attached = resize = 0;
-		TAILQ_FOREACH(wl, &w->winlinks, wentry) {
-			s = wl->session;
-			if (s->attached != 0)
-				attached = 1;
-			if (s->attached != 0 && s->curw == wl) {
-				resize = 1;
-				break;
-			}
-		}
-		if (!attached)
-			resize = 1;
 		TAILQ_FOREACH(wp, &w->panes, entry) {
 			if (wp->fd != -1) {
 				if (focus)
-					server_client_check_focus(wp);
+					server_client_check_pane_focus(wp);
-				if (resize)
+				server_client_check_pane_resize(wp);
-					server_client_check_resize(wp);
 			}
 			wp->flags &= ~PANE_REDRAW;
 		}
@@ -1389,6 +1373,26 @@ server_client_loop(void)
 	}
 }
 
+/* Check if window needs to be resized. */
+static void
+server_client_check_window_resize(struct window *w)
+{
+	struct winlink	*wl;
+
+	if (~w->flags & WINDOW_RESIZE)
+		return;
+
+	TAILQ_FOREACH(wl, &w->winlinks, wentry) {
+		if (wl->session->attached != 0 && wl->session->curw == wl)
+			break;
+	}
+	if (wl == NULL)
+		return;
+
+	log_debug("%s: resizing window @%u", __func__, w->id);
+	resize_window(w, w->new_sx, w->new_sy, w->new_xpixel, w->new_ypixel);
+}
+
 /* Check if we need to force a resize. */
 static int
 server_client_resize_force(struct window_pane *wp)
@@ -1470,7 +1474,7 @@ server_client_resize_event(__unused int fd, __unused short events, void *data)
 
 /* Check if pane should be resized. */
 static void
-server_client_check_resize(struct window_pane *wp)
+server_client_check_pane_resize(struct window_pane *wp)
 {
 	if (~wp->flags & PANE_RESIZE)
 		return;
@@ -1488,7 +1492,7 @@ server_client_check_resize(struct window_pane *wp)
 
 /* Check whether pane should be focused. */
 static void
-server_client_check_focus(struct window_pane *wp)
+server_client_check_pane_focus(struct window_pane *wp)
 {
 	struct client	*c;
 	int		 push;

tmux.h

@@ -1012,12 +1012,18 @@ struct window {
 	u_int		 xpixel;
 	u_int		 ypixel;
 
+	u_int		 new_sx;
+	u_int		 new_sy;
+	u_int		 new_xpixel;
+	u_int		 new_ypixel;
+
 	int		 flags;
 #define WINDOW_BELL 0x1
 #define WINDOW_ACTIVITY 0x2
 #define WINDOW_SILENCE 0x4
 #define WINDOW_ZOOMED 0x8
 #define WINDOW_WASZOOMED 0x10
+#define WINDOW_RESIZE 0x20
 #define WINDOW_ALERTFLAGS (WINDOW_BELL|WINDOW_ACTIVITY|WINDOW_SILENCE)
 
 	int		 alerts_queued;

window.c

@@ -438,13 +438,15 @@ window_pane_send_resize(struct window_pane *wp, int yadjust)
 {
 	struct window	*w = wp->window;
 	struct winsize	 ws;
+	u_int  		 sy = wp->sy + yadjust;
 
 	if (wp->fd == -1)
 		return;
+	log_debug("%s: %%%u resize to %u,%u", __func__, wp->id, wp->sx, sy);
 
 	memset(&ws, 0, sizeof ws);
 	ws.ws_col = wp->sx;
-	ws.ws_row = wp->sy + yadjust;
+	ws.ws_row = sy;
 	ws.ws_xpixel = w->xpixel * ws.ws_col;
 	ws.ws_ypixel = w->ypixel * ws.ws_row;
 	if (ioctl(wp->fd, TIOCSWINSZ, &ws) == -1)
@@ -1001,7 +1003,6 @@ window_pane_resize(struct window_pane *wp, u_int sx, u_int sy)
 	wme = TAILQ_FIRST(&wp->modes);
 	if (wme != NULL && wme->mode->resize != NULL)
 		wme->mode->resize(wme, sx, sy);
-
 	wp->flags |= (PANE_RESIZE|PANE_RESIZED);
 }