diff --git a/job.c b/job.c
index cab91d2c..eeb90f42 100644
--- a/job.c
+++ b/job.c
@@ -69,9 +69,10 @@ static LIST_HEAD(joblist, job) all_jobs = LIST_HEAD_INITIALIZER(all_jobs);
 
 /* Start a job running. */
 struct job *
-job_run(const char *cmd, int argc, char **argv, struct environ *e, struct session *s,
-    const char *cwd, job_update_cb updatecb, job_complete_cb completecb,
-    job_free_cb freecb, void *data, int flags, int sx, int sy)
+job_run(const char *cmd, int argc, char **argv, struct environ *e,
+    struct session *s, const char *cwd, job_update_cb updatecb,
+    job_complete_cb completecb, job_free_cb freecb, void *data, int flags,
+    int sx, int sy)
 {
 	struct job	 *job;
 	struct environ	 *env;
@@ -81,6 +82,7 @@ job_run(const char *cmd, int argc, char **argv, struct environ *e, struct sessio
 	sigset_t	  set, oldset;
 	struct winsize	  ws;
 	char		**argvp, tty[TTY_NAME_MAX], *argv0;
+	struct options	 *oo;
 
 	/*
 	 * Do not set TERM during .tmux.conf (second argument here), it is nice
@@ -91,12 +93,17 @@ job_run(const char *cmd, int argc, char **argv, struct environ *e, struct sessio
 	if (e != NULL)
 		environ_copy(e, env);
 
-	if (s != NULL)
-		shell = options_get_string(s->options, "default-shell");
-	else
-		shell = options_get_string(global_s_options, "default-shell");
-	if (!checkshell(shell))
+	if (~flags & JOB_DEFAULTSHELL)
 		shell = _PATH_BSHELL;
+	else {
+		if (s != NULL)
+			oo = s->options;
+		else
+			oo = global_s_options;
+		shell = options_get_string(oo, "default-shell");
+		if (!checkshell(shell))
+			shell = _PATH_BSHELL;
+	}
 	argv0 = shell_argv0(shell, 0);
 
 	sigfillset(&set);
diff --git a/popup.c b/popup.c
index 706295fe..97f532c0 100644
--- a/popup.c
+++ b/popup.c
@@ -717,7 +717,7 @@ popup_display(int flags, enum box_lines lines, struct cmdq_item *item, u_int px,
 
 	pd->job = job_run(shellcmd, argc, argv, env, s, cwd,
 	    popup_job_update_cb, popup_job_complete_cb, NULL, pd,
-	    JOB_NOWAIT|JOB_PTY|JOB_KEEPWRITE, jx, jy);
+	    JOB_NOWAIT|JOB_PTY|JOB_KEEPWRITE|JOB_DEFAULTSHELL, jx, jy);
 	pd->ictx = input_init(NULL, job_get_event(pd->job), &pd->palette);
 
 	server_client_set_overlay(c, 0, popup_check_cb, popup_mode_cb,
diff --git a/tmux.h b/tmux.h
index 0b14ccd0..2dc231cb 100644
--- a/tmux.h
+++ b/tmux.h
@@ -1508,6 +1508,7 @@ struct tty {
 #define TTY_HAVEXDA 0x200
 #define TTY_SYNCING 0x400
 #define TTY_HAVEDA2 0x800 /* Secondary DA. */
+#define TTY_WINSIZEQUERY 0x1000
 #define TTY_ALL_REQUEST_FLAGS \
 	(TTY_HAVEDA|TTY_HAVEDA2|TTY_HAVEXDA)
 	int		 flags;
@@ -2341,6 +2342,7 @@ typedef void (*job_free_cb) (void *);
 #define JOB_NOWAIT 0x1
 #define JOB_KEEPWRITE 0x2
 #define JOB_PTY 0x4
+#define JOB_DEFAULTSHELL 0x8
 struct job	*job_run(const char *, int, char **, struct environ *,
 		     struct session *, const char *, job_update_cb,
 		     job_complete_cb, job_free_cb, void *, int, int, int);
@@ -2403,6 +2405,7 @@ void	tty_cell(struct tty *, const struct grid_cell *,
 int	tty_init(struct tty *, struct client *);
 void	tty_resize(struct tty *);
 void	tty_set_size(struct tty *, u_int, u_int, u_int, u_int);
+void	tty_invalidate(struct tty *);
 void	tty_start_tty(struct tty *);
 void	tty_send_requests(struct tty *);
 void	tty_repeat_requests(struct tty *);
diff --git a/tty-keys.c b/tty-keys.c
index 3debeea1..3c08db11 100644
--- a/tty-keys.c
+++ b/tty-keys.c
@@ -654,6 +654,74 @@ tty_keys_next1(struct tty *tty, const char *buf, size_t len, key_code *key,
 	return (-1);
 }
 
+/* Process window size change escape sequences. */
+static int
+tty_keys_winsz(struct tty *tty, const char *buf, size_t len, size_t *size)
+{
+	struct client	*c = tty->client;
+	size_t		 end;
+	char		 tmp[64];
+	u_int		 sx, sy, xpixel, ypixel, char_x, char_y;
+
+	*size = 0;
+
+	/* If we did not request this, ignore it. */
+	if (!(tty->flags & TTY_WINSIZEQUERY))
+		return (-1);
+
+	/* First two bytes are always \033[. */
+	if (buf[0] != '\033')
+		return (-1);
+	if (len == 1)
+		return (1);
+	if (buf[1] != '[')
+		return (-1);
+	if (len == 2)
+		return (1);
+
+	/*
+	 * Stop at either 't' or anything that isn't a
+	 * number or ';'.
+	 */
+	for (end = 2; end < len && end != sizeof tmp; end++) {
+		if (buf[end] == 't')
+			break;
+		if (!isdigit((u_char)buf[end]) && buf[end] != ';')
+			break;
+	}
+	if (end == len)
+		return (1);
+	if (end == sizeof tmp || buf[end] != 't')
+		return (-1);
+
+	/* Copy to the buffer. */
+	memcpy(tmp, buf + 2, end - 2);
+	tmp[end - 2] = '\0';
+
+	/* Try to parse the window size sequence. */
+	if (sscanf(tmp, "8;%u;%u", &sy, &sx) == 2) {
+		/* Window size in characters. */
+		tty_set_size(tty, sx, sy, tty->xpixel, tty->ypixel);
+
+		*size = end + 1;
+		return (0);
+	} else if (sscanf(tmp, "4;%u;%u", &ypixel, &xpixel) == 2) {
+		/* Window size in pixels. */
+		char_x = (xpixel && tty->sx) ? xpixel / tty->sx : 0;
+		char_y = (ypixel && tty->sy) ? ypixel / tty->sy : 0;
+		tty_set_size(tty, tty->sx, tty->sy, char_x, char_y);
+		tty_invalidate(tty);
+
+		tty->flags &= ~TTY_WINSIZEQUERY;
+		*size = end + 1;
+		return (0);
+	}
+
+	log_debug("%s: unrecognized window size sequence: %s", c->name, tmp);
+	return (-1);
+}
+
+
 /* Process at least one key in the buffer. Return 0 if no keys present. */
 int
 tty_keys_next(struct tty *tty)
@@ -754,6 +822,17 @@ tty_keys_next(struct tty *tty)
 		goto partial_key;
 	}
 
+	/* Check for window size query */
+	switch (tty_keys_winsz(tty, buf, len, &size)) {
+	case 0:		/* yes */
+		key = KEYC_UNKNOWN;
+		goto complete_key;
+	case -1:	/* no, or not valid */
+		break;
+	case 1:		/* partial */
+		goto partial_key;
+	}
+
 first_key:
 	/* Try to lookup complete key. */
 	n = tty_keys_next1(tty, buf, len, &key, &size, expired);
diff --git a/tty.c b/tty.c
index 28dca400..2c9b7299 100644
--- a/tty.c
+++ b/tty.c
@@ -42,7 +42,6 @@ static void	tty_cursor_pane(struct tty *, const struct tty_ctx *, u_int,
 		    u_int);
 static void	tty_cursor_pane_unless_wrap(struct tty *,
 		    const struct tty_ctx *, u_int, u_int);
-static void	tty_invalidate(struct tty *);
 static void	tty_colours(struct tty *, const struct grid_cell *);
 static void	tty_check_fg(struct tty *, struct colour_palette *,
     		    struct grid_cell *);
@@ -140,6 +139,14 @@ tty_resize(struct tty *tty)
 			ypixel = 0;
 		} else
 			ypixel = ws.ws_ypixel / sy;
+
+		if ((xpixel == 0 || ypixel == 0) &&
+		    tty->out != NULL &&
+		    !(tty->flags & TTY_WINSIZEQUERY) &&
+		    (tty->term->flags & TERM_VT100LIKE)) {
+			tty_puts(tty, "\033[18t\033[14t");
+			tty->flags |= TTY_WINSIZEQUERY;
+		}
 	} else {
 		sx = 80;
 		sy = 24;
@@ -2369,7 +2376,7 @@ tty_reset(struct tty *tty)
 	memcpy(&tty->last_cell, &grid_default_cell, sizeof tty->last_cell);
 }
 
-static void
+void
 tty_invalidate(struct tty *tty)
 {
 	memcpy(&tty->cell, &grid_default_cell, sizeof tty->cell);