Drop having a separate type for style options and make them all strings,

which allows formats to be expanded. Any styles without a '#{' are still
validated when they are set but any with a '#{' are not. Formats are not
expanded usefully in many cases yet, that will be changed later.

To make this work, a few other changes:

- set-option -a with a style option automatically appends a ",".

- OSC 10 and 11 don't set the window-style option anymore, instead the
  fg and bg are stored in the pane struct and act as the defaults that
  can be overridden by window-style.

- status-fg and -bg now override status-style instead of trying to keep
  them in sync.

18 files changed, 510 insertions, 346 deletions

diff --git a/cmd-rename-window.c b/cmd-rename-window.c
index 1fb17ad9..593e0b9e 100644
--- a/cmd-rename-window.c
+++ b/cmd-rename-window.c
@@ -54,6 +54,7 @@ cmd_rename_window_exec(struct cmd *self, struct cmdq_item *item)
 	window_set_name(wl->window, newname);
 	options_set_number(wl->window->options, "automatic-rename", 0);
 
+	server_redraw_window_borders(wl->window);
 	server_status_window(wl->window);
 	free(newname);
 
diff --git a/cmd-resize-pane.c b/cmd-resize-pane.c
index 105f48e0..563c95fb 100644
--- a/cmd-resize-pane.c
+++ b/cmd-resize-pane.c
@@ -91,7 +91,6 @@ cmd_resize_pane_exec(struct cmd *self, struct cmdq_item *item)
 		else
 			window_zoom(wp);
 		server_redraw_window(w);
-		server_status_window(w);
 		return (CMD_RETURN_NORMAL);
 	}
 	server_unzoom_window(w);
diff --git a/cmd-respawn-pane.c b/cmd-respawn-pane.c
index 498a89a7..9db280b4 100644
--- a/cmd-respawn-pane.c
+++ b/cmd-respawn-pane.c
@@ -90,6 +90,7 @@ cmd_respawn_pane_exec(struct cmd *self, struct cmdq_item *item)
 	}
 
 	wp->flags |= PANE_REDRAW;
+	server_redraw_window_borders(wp->window);
 	server_status_window(wp->window);
 
 	environ_free(sc.environ);
diff --git a/cmd-select-pane.c b/cmd-select-pane.c
index db110ff9..224370ab 100644
--- a/cmd-select-pane.c
+++ b/cmd-select-pane.c
@@ -91,9 +91,9 @@ cmd_select_pane_exec(struct cmd *self, struct cmdq_item *item)
 	struct window		*w = wl->window;
 	struct session		*s = target->s;
 	struct window_pane	*wp = target->wp, *lastwp, *markedwp;
+	struct options		*oo = wp->options;
 	char			*title;
 	const char		*style;
-	struct style		*sy;
 	struct options_entry	*o;
 
 	if (entry == &cmd_last_pane_entry || args_has(args, 'l')) {
@@ -147,22 +147,18 @@ cmd_select_pane_exec(struct cmd *self, struct cmdq_item *item)
 		return (CMD_RETURN_NORMAL);
 	}
 
-	if (args_has(args, 'P') || args_has(args, 'g')) {
-		if ((style = args_get(args, 'P')) != NULL) {
-			o = options_set_style(wp->options, "window-style", 0,
-			    style);
-			if (o == NULL) {
-				cmdq_error(item, "bad style: %s", style);
-				return (CMD_RETURN_ERROR);
-			}
-			options_set_style(wp->options, "window-active-style", 0,
-			    style);
-			wp->flags |= (PANE_REDRAW|PANE_STYLECHANGED);
-		}
-		if (args_has(args, 'g')) {
-			sy = options_get_style(wp->options, "window-style");
-			cmdq_print(item, "%s", style_tostring(sy));
+	style = args_get(args, 'P');
+	if (style != NULL) {
+		o = options_set_string(oo, "window-style", 0, "%s", style);
+		if (o == NULL) {
+			cmdq_error(item, "bad style: %s", style);
+			return (CMD_RETURN_ERROR);
 		}
+		options_set_string(oo, "window-active-style", 0, "%s", style);
+		wp->flags |= (PANE_REDRAW|PANE_STYLECHANGED);
+	}
+	if (args_has(args, 'g')) {
+		cmdq_print(item, "%s", options_get_string(oo, "window-style"));
 		return (CMD_RETURN_NORMAL);
 	}
 
@@ -197,8 +193,10 @@ cmd_select_pane_exec(struct cmd *self, struct cmdq_item *item)
 
 	if (args_has(args, 'T')) {
 		title = format_single_from_target(item, args_get(args, 'T'));
-		if (screen_set_title(&wp->base, title))
+		if (screen_set_title(&wp->base, title)) {
+			server_redraw_window_borders(wp->window);
 			server_status_window(wp->window);
+		}
 		free(title);
 		return (CMD_RETURN_NORMAL);
 	}
diff --git a/cmd-set-option.c b/cmd-set-option.c
index 1752d093..e04aa7ff 100644
--- a/cmd-set-option.c
+++ b/cmd-set-option.c
@@ -93,7 +93,6 @@ cmd_set_option_exec(struct cmd *self, struct cmdq_item *item)
 	char				*name, *argument, *value = NULL, *cause;
 	int				 window, idx, already, error, ambiguous;
 	int				 scope;
-	struct style			*sy;
 
 	window = (cmd_get_entry(self) == &cmd_set_window_option_entry);
 
@@ -232,16 +231,6 @@ cmd_set_option_exec(struct cmd *self, struct cmdq_item *item)
 				tty_keys_build(&loop->tty);
 		}
 	}
-	if (strcmp(name, "status-fg") == 0 || strcmp(name, "status-bg") == 0) {
-		sy = options_get_style(oo, "status-style");
-		sy->gc.fg = options_get_number(oo, "status-fg");
-		sy->gc.bg = options_get_number(oo, "status-bg");
-	}
-	if (strcmp(name, "status-style") == 0) {
-		sy = options_get_style(oo, "status-style");
-		options_set_number(oo, "status-fg", sy->gc.fg);
-		options_set_number(oo, "status-bg", sy->gc.bg);
-	}
 	if (strcmp(name, "status") == 0 ||
 	    strcmp(name, "status-interval") == 0)
 		status_timer_start_all();
@@ -283,16 +272,38 @@ fail:
 }
 
 static int
+cmd_set_option_check_string(const struct options_table_entry *oe,
+    const char *value, char **cause)
+{
+	struct style	sy;
+
+	if (strcmp(oe->name, "default-shell") == 0 && !checkshell(value)) {
+		xasprintf(cause, "not a suitable shell: %s", value);
+		return (-1);
+	}
+	if (oe->pattern != NULL && fnmatch(oe->pattern, value, 0) != 0) {
+		xasprintf(cause, "value is invalid: %s", value);
+		return (-1);
+	}
+	if ((oe->flags & OPTIONS_TABLE_IS_STYLE) &&
+	    strstr(value, "#{") == NULL &&
+	    style_parse(&sy, &grid_default_cell, value) != 0) {
+		xasprintf(cause, "invalid style: %s", value);
+		return (-1);
+	}
+	return (0);
+}
+
+static int
 cmd_set_option_set(struct cmd *self, struct cmdq_item *item, struct options *oo,
     struct options_entry *parent, const char *value)
 {
 	const struct options_table_entry	*oe;
 	struct args				*args = cmd_get_args(self);
 	int					 append = args_has(args, 'a');
-	struct options_entry			*o;
 	long long				 number;
 	const char				*errstr, *new;
-	char					*old;
+	char					*old, *cause;
 	key_code				 key;
 
 	oe = options_table_entry(parent);
@@ -308,17 +319,12 @@ cmd_set_option_set(struct cmd *self, struct cmdq_item *item, struct options *oo,
 		old = xstrdup(options_get_string(oo, oe->name));
 		options_set_string(oo, oe->name, append, "%s", value);
 		new = options_get_string(oo, oe->name);
-		if (strcmp(oe->name, "default-shell") == 0 &&
-		    !checkshell(new)) {
-			options_set_string(oo, oe->name, 0, "%s", old);
-			free(old);
-			cmdq_error(item, "not a suitable shell: %s", value);
-			return (-1);
-		}
-		if (oe->pattern != NULL && fnmatch(oe->pattern, new, 0) != 0) {
+		if (cmd_set_option_check_string(oe, new, &cause) != 0) {
+			cmdq_error(item, "%s", cause);
+			free(cause);
+
 			options_set_string(oo, oe->name, 0, "%s", old);
 			free(old);
-			cmdq_error(item, "value is invalid: %s", value);
 			return (-1);
 		}
 		free(old);
@@ -350,13 +356,6 @@ cmd_set_option_set(struct cmd *self, struct cmdq_item *item, struct options *oo,
 		return (cmd_set_option_flag(item, oe, oo, value));
 	case OPTIONS_TABLE_CHOICE:
 		return (cmd_set_option_choice(item, oe, oo, value));
-	case OPTIONS_TABLE_STYLE:
-		o = options_set_style(oo, oe->name, append, value);
-		if (o == NULL) {
-			cmdq_error(item, "bad style: %s", value);
-			return (-1);
-		}
-		return (0);
 	case OPTIONS_TABLE_COMMAND:
 		break;
 	}
diff --git a/input.c b/input.c
index b62b1858..8485a17a 100644
--- a/input.c
+++ b/input.c
@@ -1861,8 +1861,10 @@ input_csi_dispatch_winops(struct input_ctx *ictx)
 			case 0:
 			case 2:
 				screen_pop_title(sctx->s);
-				if (wp != NULL)
+				if (wp != NULL) {
+					server_redraw_window_borders(wp->window);
 					server_status_window(wp->window);
+				}
 				break;
 			}
 			break;
@@ -2253,8 +2255,10 @@ input_exit_osc(struct input_ctx *ictx)
 	switch (option) {
 	case 0:
 	case 2:
-		if (screen_set_title(sctx->s, p) && wp != NULL)
-			server_status_window(ictx->wp->window);
+		if (screen_set_title(sctx->s, p) && wp != NULL) {
+			server_redraw_window_borders(wp->window);
+			server_status_window(wp->window);
+		}
 		break;
 	case 4:
 		input_osc_4(ictx, p);
@@ -2262,8 +2266,10 @@ input_exit_osc(struct input_ctx *ictx)
 	case 7:
 		if (utf8_isvalid(p)) {
 			screen_set_path(sctx->s, p);
-			if (wp != NULL)
+			if (wp != NULL) {
+				server_redraw_window_borders(wp->window);
 				server_status_window(wp->window);
+			}
 		}
 		break;
 	case 10:
@@ -2314,8 +2320,10 @@ input_exit_apc(struct input_ctx *ictx)
 		return;
 	log_debug("%s: \"%s\"", __func__, ictx->input_buf);
 
-	if (screen_set_title(sctx->s, ictx->input_buf) && wp != NULL)
+	if (screen_set_title(sctx->s, ictx->input_buf) && wp != NULL) {
+		server_redraw_window_borders(wp->window);
 		server_status_window(wp->window);
+	}
 }
 
 /* Rename string started. */
@@ -2355,6 +2363,7 @@ input_exit_rename(struct input_ctx *ictx)
 	}
 	window_set_name(wp->window, ictx->input_buf);
 	options_set_number(wp->window->options, "automatic-rename", 0);
+	server_redraw_window_borders(wp->window);
 	server_status_window(wp->window);
 }
 
@@ -2486,7 +2495,6 @@ input_osc_10(struct input_ctx *ictx, const char *p)
 {
 	struct window_pane	*wp = ictx->wp;
 	u_int			 r, g, b;
-	char			 tmp[16];
 
 	if (wp == NULL)
 		return;
@@ -2495,9 +2503,7 @@ input_osc_10(struct input_ctx *ictx, const char *p)
 
 	if (!input_osc_parse_colour(p, &r, &g, &b))
 		goto bad;
-	xsnprintf(tmp, sizeof tmp, "fg=#%02x%02x%02x", r, g, b);
-	options_set_style(wp->options, "window-style", 1, tmp);
-	options_set_style(wp->options, "window-active-style", 1, tmp);
+	wp->fg = colour_join_rgb(r, g, b);
 	wp->flags |= (PANE_REDRAW|PANE_STYLECHANGED);
 
 	return;
@@ -2512,7 +2518,6 @@ input_osc_11(struct input_ctx *ictx, const char *p)
 {
 	struct window_pane	*wp = ictx->wp;
 	u_int			 r, g, b;
-	char			 tmp[16];
 
 	if (wp == NULL)
 		return;
@@ -2521,9 +2526,7 @@ input_osc_11(struct input_ctx *ictx, const char *p)
 
 	if (!input_osc_parse_colour(p, &r, &g, &b))
 	    goto bad;
-	xsnprintf(tmp, sizeof tmp, "bg=#%02x%02x%02x", r, g, b);
-	options_set_style(wp->options, "window-style", 1, tmp);
-	options_set_style(wp->options, "window-active-style", 1, tmp);
+	wp->bg = colour_join_rgb(r, g, b);
 	wp->flags |= (PANE_REDRAW|PANE_STYLECHANGED);
 
 	return;
diff --git a/menu.c b/menu.c
index fd744e7d..2f92af34 100644
--- a/menu.c
+++ b/menu.c
@@ -151,8 +151,7 @@ menu_draw_cb(struct client *c, __unused struct screen_redraw_ctx *ctx0)
 	u_int			 i, px = md->px, py = md->py;
 	struct grid_cell	 gc;
 
-	memcpy(&gc, &grid_default_cell, sizeof gc);
-	style_apply(&gc, c->session->curw->window->options, "mode-style");
+	style_apply(&gc, c->session->curw->window->options, "mode-style", NULL);
 
 	screen_write_start(&ctx, NULL, s);
 	screen_write_clearscreen(&ctx, 8);
diff --git a/mode-tree.c b/mode-tree.c
index 783ffcfa..645e2ae9 100644
--- a/mode-tree.c
+++ b/mode-tree.c
@@ -557,7 +557,7 @@ mode_tree_draw(struct mode_tree_data *mtd)
 
 	memcpy(&gc0, &grid_default_cell, sizeof gc0);
 	memcpy(&gc, &grid_default_cell, sizeof gc);
-	style_apply(&gc, oo, "mode-style");
+	style_apply(&gc, oo, "mode-style", NULL);
 
 	w = mtd->width;
 	h = mtd->height;
diff --git a/names.c b/names.c
index 661ba06e..07c689d1 100644
--- a/names.c
+++ b/names.c
@@ -96,6 +96,7 @@ check_window_name(struct window *w)
 	if (strcmp(name, w->name) != 0) {
 		log_debug("@%u new name %s (was %s)", w->id, name, w->name);
 		window_set_name(w, name);
+		server_redraw_window_borders(w);
 		server_status_window(w);
 	} else
 		log_debug("@%u name not changed (still %s)", w->id, w->name);
diff --git a/options-table.c b/options-table.c
index eaa7c2a7..5c368586 100644
--- a/options-table.c
+++ b/options-table.c
@@ -401,15 +401,19 @@ const struct options_table_entry options_table[] = {
 	},
 
 	{ .name = "message-command-style",
-	  .type = OPTIONS_TABLE_STYLE,
+	  .type = OPTIONS_TABLE_STRING,
 	  .scope = OPTIONS_TABLE_SESSION,
-	  .default_str = "bg=black,fg=yellow"
+	  .default_str = "bg=black,fg=yellow",
+	  .flags = OPTIONS_TABLE_IS_STYLE,
+	  .separator = ","
 	},
 
 	{ .name = "message-style",
-	  .type = OPTIONS_TABLE_STYLE,
+	  .type = OPTIONS_TABLE_STRING,
 	  .scope = OPTIONS_TABLE_SESSION,
-	  .default_str = "bg=yellow,fg=black"
+	  .default_str = "bg=yellow,fg=black",
+	  .flags = OPTIONS_TABLE_IS_STYLE,
+	  .separator = ","
 	},
 
 	{ .name = "mouse",
@@ -473,13 +477,13 @@ const struct options_table_entry options_table[] = {
 	{ .name = "status-bg",
 	  .type = OPTIONS_TABLE_COLOUR,
 	  .scope = OPTIONS_TABLE_SESSION,
-	  .default_num = 2,
+	  .default_num = 8,
 	},
 
 	{ .name = "status-fg",
 	  .type = OPTIONS_TABLE_COLOUR,
 	  .scope = OPTIONS_TABLE_SESSION,
-	  .default_num = 0,
+	  .default_num = 8,
 	},
 
 	{ .name = "status-format",
@@ -526,9 +530,11 @@ const struct options_table_entry options_table[] = {
 	},
 
 	{ .name = "status-left-style",
-	  .type = OPTIONS_TABLE_STYLE,
+	  .type = OPTIONS_TABLE_STRING,
 	  .scope = OPTIONS_TABLE_SESSION,
-	  .default_str = "default"
+	  .default_str = "default",
+	  .flags = OPTIONS_TABLE_IS_STYLE,
+	  .separator = ","
 	},
 
 	{ .name = "status-position",
@@ -555,15 +561,19 @@ const struct options_table_entry options_table[] = {
 	},
 
 	{ .name = "status-right-style",
-	  .type = OPTIONS_TABLE_STYLE,
+	  .type = OPTIONS_TABLE_STRING,
 	  .scope = OPTIONS_TABLE_SESSION,
-	  .default_str = "default"
+	  .default_str = "default",
+	  .flags = OPTIONS_TABLE_IS_STYLE,
+	  .separator = ","
 	},
 
 	{ .name = "status-style",
-	  .type = OPTIONS_TABLE_STYLE,
+	  .type = OPTIONS_TABLE_STRING,
 	  .scope = OPTIONS_TABLE_SESSION,
-	  .default_str = "bg=green,fg=black"
+	  .default_str = "bg=green,fg=black",
+	  .flags = OPTIONS_TABLE_IS_STYLE,
+	  .separator = ","
 	},
 
 	{ .name = "update-environment",
@@ -666,9 +676,11 @@ const struct options_table_entry options_table[] = {
 	},
 
 	{ .name = "mode-style",
-	  .type = OPTIONS_TABLE_STYLE,
+	  .type = OPTIONS_TABLE_STRING,
 	  .scope = OPTIONS_TABLE_WINDOW,
-	  .default_str = "bg=yellow,fg=black"
+	  .default_str = "bg=yellow,fg=black",
+	  .flags = OPTIONS_TABLE_IS_STYLE,
+	  .separator = ","
 	},
 
 	{ .name = "monitor-activity",
@@ -704,9 +716,11 @@ const struct options_table_entry options_table[] = {
 	},
 
 	{ .name = "pane-active-border-style",
-	  .type = OPTIONS_TABLE_STYLE,
+	  .type = OPTIONS_TABLE_STRING,
 	  .scope = OPTIONS_TABLE_WINDOW,
-	  .default_str = "fg=green"
+	  .default_str = "#{?pane_in_mode,fg=yellow,#{?synchronize-panes,fg=red,fg=green}}",
+	  .flags = OPTIONS_TABLE_IS_STYLE,
+	  .separator = ","
 	},
 
 	{ .name = "pane-base-index",
@@ -732,9 +746,11 @@ const struct options_table_entry options_table[] = {
 	},
 
 	{ .name = "pane-border-style",
-	  .type = OPTIONS_TABLE_STYLE,
+	  .type = OPTIONS_TABLE_STRING,
 	  .scope = OPTIONS_TABLE_WINDOW,
-	  .default_str = "default"
+	  .default_str = "default",
+	  .flags = OPTIONS_TABLE_IS_STYLE,
+	  .separator = ","
 	},
 
 	{ .name = "remain-on-exit",
@@ -750,9 +766,11 @@ const struct options_table_entry options_table[] = {
 	},
 
 	{ .name = "window-active-style",
-	  .type = OPTIONS_TABLE_STYLE,
+	  .type = OPTIONS_TABLE_STRING,
 	  .scope = OPTIONS_TABLE_WINDOW|OPTIONS_TABLE_PANE,
-	  .default_str = "default"
+	  .default_str = "default",
+	  .flags = OPTIONS_TABLE_IS_STYLE,
+	  .separator = ","
 	},
 
 	{ .name = "window-size",
@@ -763,21 +781,27 @@ const struct options_table_entry options_table[] = {
 	},
 
 	{ .name = "window-style",
-	  .type = OPTIONS_TABLE_STYLE,
+	  .type = OPTIONS_TABLE_STRING,
 	  .scope = OPTIONS_TABLE_WINDOW|OPTIONS_TABLE_PANE,
-	  .default_str = "default"
+	  .default_str = "default",
+	  .flags = OPTIONS_TABLE_IS_STYLE,
+	  .separator = ","
 	},
 
 	{ .name = "window-status-activity-style",
-	  .type = OPTIONS_TABLE_STYLE,
+	  .type = OPTIONS_TABLE_STRING,
 	  .scope = OPTIONS_TABLE_WINDOW,
-	  .default_str = "reverse"
+	  .default_str = "reverse",
+	  .flags = OPTIONS_TABLE_IS_STYLE,
+	  .separator = ","
 	},
 
 	{ .name = "window-status-bell-style",
-	  .type = OPTIONS_TABLE_STYLE,
+	  .type = OPTIONS_TABLE_STRING,
 	  .scope = OPTIONS_TABLE_WINDOW,
-	  .default_str = "reverse"
+	  .default_str = "reverse",
+	  .flags = OPTIONS_TABLE_IS_STYLE,
+	  .separator = ","
 	},
 
 	{ .name = "window-status-current-format",
@@ -787,9 +811,11 @@ const struct options_table_entry options_table[] = {
 	},
 
 	{ .name = "window-status-current-style",
-	  .type = OPTIONS_TABLE_STYLE,
+	  .type = OPTIONS_TABLE_STRING,
 	  .scope = OPTIONS_TABLE_WINDOW,
-	  .default_str = "default"
+	  .default_str = "default",
+	  .flags = OPTIONS_TABLE_IS_STYLE,
+	  .separator = ","
 	},
 
 	{ .name = "window-status-format",
@@ -799,9 +825,11 @@ const struct options_table_entry options_table[] = {
 	},
 
 	{ .name = "window-status-last-style",
-	  .type = OPTIONS_TABLE_STYLE,
+	  .type = OPTIONS_TABLE_STRING,
 	  .scope = OPTIONS_TABLE_WINDOW,
-	  .default_str = "default"
+	  .default_str = "default",
+	  .flags = OPTIONS_TABLE_IS_STYLE,
+	  .separator = ","
 	},
 
 	{ .name = "window-status-separator",
@@ -811,9 +839,11 @@ const struct options_table_entry options_table[] = {
 	},
 
 	{ .name = "window-status-style",
-	  .type = OPTIONS_TABLE_STYLE,
+	  .type = OPTIONS_TABLE_STRING,
 	  .scope = OPTIONS_TABLE_WINDOW,
-	  .default_str = "default"
+	  .default_str = "default",
+	  .flags = OPTIONS_TABLE_IS_STYLE,
+	  .separator = ","
 	},
 
 	{ .name = "wrap-search",
diff --git a/options.c b/options.c
index 7402b724..39a0d08f 100644
--- a/options.c
+++ b/options.c
@@ -53,6 +53,9 @@ struct options_entry {
 	const struct options_table_entry	*tableentry;
 	union options_value			 value;
 
+	int					 cached;
+	struct style				 style;
+
 	RB_ENTRY(options_entry)			 entry;
 };
 
@@ -73,9 +76,6 @@ static struct options_entry	*options_add(struct options *, const char *);
 	    (o)->tableentry->type == OPTIONS_TABLE_COLOUR ||		\
 	    (o)->tableentry->type == OPTIONS_TABLE_FLAG ||		\
 	    (o)->tableentry->type == OPTIONS_TABLE_CHOICE))
-#define OPTIONS_IS_STYLE(o) \
-	((o)->tableentry != NULL &&					\
-	    (o)->tableentry->type == OPTIONS_TABLE_STYLE)
 #define OPTIONS_IS_COMMAND(o) \
 	((o)->tableentry != NULL &&					\
 	    (o)->tableentry->type == OPTIONS_TABLE_COMMAND)
@@ -123,8 +123,6 @@ options_value_tostring(struct options_entry *o, union options_value *ov,
 
 	if (OPTIONS_IS_COMMAND(o))
 		return (cmd_list_print(ov->cmdlist, 0));
-	if (OPTIONS_IS_STYLE(o))
-		return (xstrdup(style_tostring(&ov->style)));
 	if (OPTIONS_IS_NUMBER(o)) {
 		switch (o->tableentry->type) {
 		case OPTIONS_TABLE_NUMBER:
@@ -146,7 +144,6 @@ options_value_tostring(struct options_entry *o, union options_value *ov,
 			s = xstrdup(o->tableentry->choices[ov->number]);
 			break;
 		case OPTIONS_TABLE_STRING:
-		case OPTIONS_TABLE_STYLE:
 		case OPTIONS_TABLE_COMMAND:
 			fatalx("not a number option type");
 		}
@@ -258,10 +255,6 @@ options_default(struct options *oo, const struct options_table_entry *oe)
 	case OPTIONS_TABLE_STRING:
 		ov->string = xstrdup(oe->default_str);
 		break;
-	case OPTIONS_TABLE_STYLE:
-		style_set(&ov->style, &grid_default_cell);
-		style_parse(&ov->style, &grid_default_cell, oe->default_str);
-		break;
 	default:
 		ov->number = oe->default_num;
 		break;
@@ -653,25 +646,13 @@ options_get_number(struct options *oo, const char *name)
 	return (o->value.number);
 }
 
-struct style *
-options_get_style(struct options *oo, const char *name)
-{
-	struct options_entry	*o;
-
-	o = options_get(oo, name);
-	if (o == NULL)
-		fatalx("missing option %s", name);
-	if (!OPTIONS_IS_STYLE(o))
-		fatalx("option %s is not a style", name);
-	return (&o->value.style);
-}
-
 struct options_entry *
 options_set_string(struct options *oo, const char *name, int append,
     const char *fmt, ...)
 {
 	struct options_entry	*o;
 	va_list			 ap;
+	const char		*separator = "";
 	char			*s, *value;
 
 	va_start(ap, fmt);
@@ -680,7 +661,12 @@ options_set_string(struct options *oo, const char *name, int append,
 
 	o = options_get_only(oo, name);
 	if (o != NULL && append && OPTIONS_IS_STRING(o)) {
-		xasprintf(&value, "%s%s", o->value.string, s);
+		if (*name != '@') {
+			separator = o->tableentry->separator;
+			if (separator == NULL)
+				separator = "";
+		}
+		xasprintf(&value, "%s%s%s", o->value.string, separator, s);
 		free(s);
 	} else
 		value = s;
@@ -696,6 +682,7 @@ options_set_string(struct options *oo, const char *name, int append,
 		fatalx("option %s is not a string", name);
 	free(o->value.string);
 	o->value.string = value;
+	o->cached = 0;
 	return (o);
 }
 
@@ -720,35 +707,6 @@ options_set_number(struct options *oo, const char *name, long long value)
 	return (o);
 }
 
-struct options_entry *
-options_set_style(struct options *oo, const char *name, int append,
-    const char *value)
-{
-	struct options_entry	*o;
-	struct style		 sy;
-
-	if (*name == '@')
-		fatalx("user option %s must be a string", name);
-
-	o = options_get_only(oo, name);
-	if (o != NULL && append && OPTIONS_IS_STYLE(o))
-		style_copy(&sy, &o->value.style);
-	else
-		style_set(&sy, &grid_default_cell);
-	if (style_parse(&sy, &grid_default_cell, value) == -1)
-		return (NULL);
-	if (o == NULL) {
-		o = options_default(oo, options_parent_table_entry(oo, name));
-		if (o == NULL)
-			return (NULL);
-	}
-
-	if (!OPTIONS_IS_STYLE(o))
-		fatalx("option %s is not a style", name);
-	style_copy(&o->value.style, &sy);
-	return (o);
-}
-
 int
 options_scope_from_name(struct args *args, int window,
     const char *name, struct cmd_find_state *fs, struct options **oo,
@@ -874,3 +832,37 @@ options_scope_from_flags(struct args *args, int window,
 		return (OPTIONS_TABLE_SESSION);
 	}
 }
+
+struct style *
+options_string_to_style(struct options *oo, const char *name,
+    struct format_tree *ft)
+{
+	struct options_entry	*o;
+	const char		*s;
+	char			*expanded;
+
+	o = options_get(oo, name);
+	if (o == NULL || !OPTIONS_IS_STRING(o))
+		return (NULL);
+
+	if (o->cached)
+		return (&o->style);
+	s = o->value.string;
+	log_debug("%s: %s is '%s'", __func__, name, s);
+
+	style_set(&o->style, &grid_default_cell);
+	o->cached = (strstr(s, "#{") == NULL);
+
+	if (ft != NULL && !o->cached) {
+		expanded = format_expand(ft, s);
+		if (style_parse(&o->style, &grid_default_cell, expanded) != 0) {
+			free(expanded);
+			return (NULL);
+		}
+		free(expanded);
+	} else {
+		if (style_parse(&o->style, &grid_default_cell, s) != 0)
+			return (NULL);
+	}
+	return (&o->style);
+}
diff --git a/screen-redraw.c b/screen-redraw.c
index 5ca6024d..19ed6305 100644
--- a/screen-redraw.c
+++ b/screen-redraw.c
@@ -45,54 +45,197 @@ static void	screen_redraw_draw_pane(struct screen_redraw_ctx *,
 
 #define CELL_BORDERS " xqlkmjwvtun~"
 
-/* Check if cell is on the border of a particular pane. */
+const struct grid_cell screen_redraw_border_cell = {
+	{ { ' ' }, 0, 1, 1 }, GRID_ATTR_CHARSET, 0, 8, 8, 0
+};
+
+enum screen_redraw_border_type {
+	SCREEN_REDRAW_OUTSIDE,
+	SCREEN_REDRAW_INSIDE,
+	SCREEN_REDRAW_BORDER
+};
+
+/* Return if window has only two panes. */
 static int
-screen_redraw_cell_border1(struct window_pane *wp, u_int px, u_int py)
+screen_redraw_two_panes(struct window *w, int direction)
 {
-	/* Inside pane. */
-	if (px >= wp->xoff && px < wp->xoff + wp->sx &&
-	    py >= wp->yoff && py < wp->yoff + wp->sy)
+	struct window_pane	*wp;
+
+	wp = TAILQ_NEXT(TAILQ_FIRST(&w->panes), entry);
+	if (wp == NULL)
+		return (0); /* one pane */
+	if (TAILQ_NEXT(wp, entry) != NULL)
+		return (0); /* more than two panes */
+	if (direction == 0 && wp->xoff == 0)
+		return (0);
+	if (direction == 1 && wp->yoff == 0)
 		return (0);
+	return (1);
+}
+
+/* Check if cell is on the border of a pane. */
+static enum screen_redraw_border_type
+screen_redraw_pane_border(struct window_pane *wp, u_int px, u_int py,
+    int pane_status)
+{
+	u_int	ex = wp->xoff + wp->sx, ey = wp->yoff + wp->sy;
+
+	/* Inside pane. */
+	if (px >= wp->xoff && px < ex && py >= wp->yoff && py < ey)
+		return (SCREEN_REDRAW_INSIDE);
 
 	/* Left/right borders. */
-	if ((wp->yoff == 0 || py >= wp->yoff - 1) && py <= wp->yoff + wp->sy) {
-		if (wp->xoff != 0 && px == wp->xoff - 1)
-			return (1);
-		if (px == wp->xoff + wp->sx)
-			return (2);
+	if (pane_status == PANE_STATUS_OFF) {
+		if (screen_redraw_two_panes(wp->window, 0)) {
+			if (wp->xoff == 0 && px == wp->sx && py <= wp->sy / 2)
+				return (SCREEN_REDRAW_BORDER);
+			if (wp->xoff != 0 &&
+			    px == wp->xoff - 1 &&
+			    py > wp->sy / 2)
+				return (SCREEN_REDRAW_BORDER);
+		} else {
+			if ((wp->yoff == 0 || py >= wp->yoff - 1) && py <= ey) {
+				if (wp->xoff != 0 && px == wp->xoff - 1)
+					return (SCREEN_REDRAW_BORDER);
+				if (px == ex)
+					return (SCREEN_REDRAW_BORDER);
+			}
+		}
+	} else {
+		if ((wp->yoff == 0 || py >= wp->yoff - 1) && py <= ey) {
+			if (wp->xoff != 0 && px == wp->xoff - 1)
+				return (SCREEN_REDRAW_BORDER);
+			if (px == ex)
+				return (SCREEN_REDRAW_BORDER);
+		}
 	}
 
 	/* Top/bottom borders. */
-	if ((wp->xoff == 0 || px >= wp->xoff - 1) && px <= wp->xoff + wp->sx) {
-		if (wp->yoff != 0 && py == wp->yoff - 1)
-			return (3);
-		if (py == wp->yoff + wp->sy)
-			return (4);
+	if (pane_status == PANE_STATUS_OFF) {
+		if (screen_redraw_two_panes(wp->window, 1)) {
+			if (wp->yoff == 0 && py == wp->sy && px <= wp->sx / 2)
+				return (SCREEN_REDRAW_BORDER);
+			if (wp->yoff != 0 &&
+			    py == wp->yoff - 1 &&
+			    px > wp->sx / 2)
+				return (SCREEN_REDRAW_BORDER);
+		} else {
+			if ((wp->xoff == 0 || px >= wp->xoff - 1) && px <= ex) {
+				if (wp->yoff != 0 && py == wp->yoff - 1)
+					return (SCREEN_REDRAW_BORDER);
+				if (py == ey)
+					return (SCREEN_REDRAW_BORDER);
+			}
+		}
+	} else if (pane_status == PANE_STATUS_TOP) {
+		if ((wp->xoff == 0 || px >= wp->xoff - 1) && px <= ex) {
+			if (wp->yoff != 0 && py == wp->yoff - 1)
+				return (SCREEN_REDRAW_BORDER);
+		}
+	} else {
+		if ((wp->xoff == 0 || px >= wp->xoff - 1) && px <= ex) {
+			if (py == ey)
+				return (SCREEN_REDRAW_BORDER);
+		}
 	}
 
 	/* Outside pane. */
-	return (-1);
+	return (SCREEN_REDRAW_OUTSIDE);
 }
 
-/* Check if a cell is on the pane border. */
+/* Check if a cell is on a border. */
 static int
-screen_redraw_cell_border(struct client *c, u_int px, u_int py)
+screen_redraw_cell_border(struct client *c, u_int px, u_int py, int pane_status)
 {
 	struct window		*w = c->session->curw->window;
 	struct window_pane	*wp;
-	int			 retval;
+
+	/* Outside the window? */
+	if (px > w->sx || py > w->sy)
+		return (0);
+
+	/* On the window border? */
+	if (px == w->sx || py == w->sy)
+		return (1);
 
 	/* Check all the panes. */
 	TAILQ_FOREACH(wp, &w->panes, entry) {
 		if (!window_pane_visible(wp))
 			continue;
-		if ((retval = screen_redraw_cell_border1(wp, px, py)) != -1)
-			return (!!retval);
+		switch (screen_redraw_pane_border(wp, px, py, pane_status)) {
+		case SCREEN_REDRAW_INSIDE:
+			return (0);
+		case SCREEN_REDRAW_BORDER:
+			return (1);
+		case SCREEN_REDRAW_OUTSIDE:
+			break;
+		}
 	}
 
 	return (0);
 }
 
+/* Work out type of border cell from surrounding cells. */
+static int
+screen_redraw_type_of_cell(struct client *c, u_int px, u_int py,
+    int pane_status)
+{
+	struct window	*w = c->session->curw->window;
+	u_int		 sx = w->sx, sy = w->sy;
+	int		 borders = 0;
+
+	/*
+	 * Construct a bitmask of whether the cells to the left (bit 4), right,
+	 * top, and bottom (bit 1) of this cell are borders.
+	 */
+	if (px == 0 || screen_redraw_cell_border(c, px - 1, py, pane_status))
+		borders |= 8;
+	if (px <= sx && screen_redraw_cell_border(c, px + 1, py, pane_status))
+		borders |= 4;
+	if (pane_status == PANE_STATUS_TOP) {
+		if (py != 0 &&
+		    screen_redraw_cell_border(c, px, py - 1, pane_status))
+			borders |= 2;
+	} else {
+		if (py == 0 ||
+		    screen_redraw_cell_border(c, px, py - 1, pane_status))
+		    borders |= 2;
+	}
+	if (py <= sy && screen_redraw_cell_border(c, px, py + 1, pane_status))
+		borders |= 1;
+
+	/*
+	 * Figure out what kind of border this cell is. Only one bit set
+	 * doesn't make sense (can't have a border cell with no others
+	 * connected).
+	 */
+	switch (borders) {
+	case 15:	/* 1111, left right top bottom */
+		return (CELL_JOIN);
+	case 14:	/* 1110, left right top */
+		return (CELL_BOTTOMJOIN);
+	case 13:	/* 1101, left right bottom */
+		return (CELL_TOPJOIN);
+	case 12:	/* 1100, left right */
+		return (CELL_TOPBOTTOM);
+	case 11:	/* 1011, left top bottom */
+		return (CELL_RIGHTJOIN);
+	case 10:	/* 1010, left top */
+		return (CELL_BOTTOMRIGHT);
+	case 9:		/* 1001, left bottom */
+		return (CELL_TOPRIGHT);
+	case 7:		/* 0111, right top bottom */
+		return (CELL_LEFTJOIN);
+	case 6:		/* 0110, right top */
+		return (CELL_BOTTOMLEFT);
+	case 5:		/* 0101, right bottom */
+		return (CELL_TOPLEFT);
+	case 3:		/* 0011, top bottom */
+		return (CELL_LEFTRIGHT);
+	}
+	return (CELL_OUTSIDE);
+}
+
 /* Check if cell inside a pane. */
 static int
 screen_redraw_check_cell(struct client *c, u_int px, u_int py, int pane_status,
@@ -100,18 +243,21 @@ screen_redraw_check_cell(struc