diff --git a/cmd-choose-window.c b/cmd-choose-window.c
index f8318105..e341dd41 100644
--- a/cmd-choose-window.c
+++ b/cmd-choose-window.c
@@ -81,11 +81,11 @@ cmd_choose_window_exec(struct cmd *self, struct cmd_ctx *ctx)
 		idx++;
 
 		flag = ' ';
-		if (session_alert_has(s, wm, WINDOW_ACTIVITY))
+		if (wm->flags & WINLINK_ACTIVITY)
 			flag = '#';
-		else if (session_alert_has(s, wm, WINDOW_BELL))
+		else if (wm->flags & WINLINK_BELL)
 			flag = '!';
-		else if (session_alert_has(s, wm, WINDOW_CONTENT))
+		else if (wm->flags & WINLINK_CONTENT)
 			flag = '+';
 		else if (wm == s->curw)
 			flag = '*';
diff --git a/cmd-new-window.c b/cmd-new-window.c
index cf32f29e..32c42eb4 100644
--- a/cmd-new-window.c
+++ b/cmd-new-window.c
@@ -162,7 +162,7 @@ cmd_new_window_exec(struct cmd *self, struct cmd_ctx *ctx)
 		 * Can't use session_detach as it will destroy session if this
 		 * makes it empty.
 		 */
-		session_alert_cancel(s, wl);
+		wl->flags &= ~WINLINK_ALERTFLAGS;
 		winlink_stack_remove(&s->lastw, wl);
 		winlink_remove(&s->windows, wl);
 
diff --git a/resize.c b/resize.c
index 5635f9d4..15f99e7c 100644
--- a/resize.c
+++ b/resize.c
@@ -105,7 +105,7 @@ recalculate_sizes(void)
 			if (flag)
 				has = s->curw->window == w;
 			else
-				has = session_has(s, w);
+				has = session_has(s, w) != NULL;
 			if (has) {
 				if (s->sx < ssx)
 					ssx = s->sx;
diff --git a/server-fn.c b/server-fn.c
index 01e78ba2..da156e46 100644
--- a/server-fn.c
+++ b/server-fn.c
@@ -184,7 +184,7 @@ server_status_window(struct window *w)
 
 	for (i = 0; i < ARRAY_LENGTH(&sessions); i++) {
 		s = ARRAY_ITEM(&sessions, i);
-		if (s != NULL && session_has(s, w))
+		if (s != NULL && session_has(s, w) != NULL)
 			server_status_session(s);
 	}
 }
@@ -249,7 +249,7 @@ server_kill_window(struct window *w)
 
 	for (i = 0; i < ARRAY_LENGTH(&sessions); i++) {
 		s = ARRAY_ITEM(&sessions, i);
-		if (s == NULL || !session_has(s, w))
+		if (s == NULL || session_has(s, w) == NULL)
 			continue;
 		while ((wl = winlink_find_by_window(&s->windows, w)) != NULL) {
 			if (session_detach(s, wl)) {
@@ -286,7 +286,7 @@ server_link_window(struct session *src, struct winlink *srcwl,
 			 * Can't use session_detach as it will destroy session
 			 * if this makes it empty.
 			 */
-			session_alert_cancel(dst, dstwl);
+			dstwl->flags &= ~WINLINK_ALERTFLAGS;
 			winlink_stack_remove(&dst->lastw, dstwl);
 			winlink_remove(&dst->windows, dstwl);
 
diff --git a/server-window.c b/server-window.c
index acac83c0..42a4a699 100644
--- a/server-window.c
+++ b/server-window.c
@@ -24,10 +24,10 @@
 #include "tmux.h"
 
 int	server_window_backoff(struct window_pane *);
-int	server_window_check_bell(struct session *, struct window *);
-int	server_window_check_activity(struct session *, struct window *);
+int	server_window_check_bell(struct session *, struct winlink *);
+int	server_window_check_activity(struct session *, struct winlink *);
 int	server_window_check_content(
-	    struct session *, struct window *, struct window_pane *);
+	    struct session *, struct winlink *, struct window_pane *);
 
 /* Check if this window should suspend reading. */
 int
@@ -59,6 +59,7 @@ void
 server_window_loop(void)
 {
 	struct window		*w;
+	struct winlink		*wl;
 	struct window_pane	*wp;
 	struct session		*s;
 	u_int		 	 i, j;
@@ -81,33 +82,37 @@ server_window_loop(void)
 
 		for (j = 0; j < ARRAY_LENGTH(&sessions); j++) {
 			s = ARRAY_ITEM(&sessions, j);
-			if (s == NULL || !session_has(s, w))
+			if (s == NULL)
+				continue;
+			wl = session_has(s, w);
+			if (wl == NULL)
 				continue;
 
-			if (server_window_check_bell(s, w) ||
-			    server_window_check_activity(s, w))
+			if (server_window_check_bell(s, wl) ||
+			    server_window_check_activity(s, wl))
 				server_status_session(s);
 			TAILQ_FOREACH(wp, &w->panes, entry)
-				server_window_check_content(s, w, wp);
+				server_window_check_content(s, wl, wp);
 		}
-		w->flags &= ~(WINDOW_BELL|WINDOW_ACTIVITY|WINDOW_CONTENT);
+		w->flags &= ~(WINDOW_BELL|WINDOW_ACTIVITY);
 	}
 }
 
 /* Check for bell in window. */
 int
-server_window_check_bell(struct session *s, struct window *w)
+server_window_check_bell(struct session *s, struct winlink *wl)
 {
 	struct client	*c;
+	struct window	*w = wl->window;
 	u_int		 i;
 	int		 action, visual;
 
-	if (!(w->flags & WINDOW_BELL))
+	if (!(w->flags & WINDOW_BELL) || wl->flags & WINLINK_BELL)
+		return (0);
+	if (s->curw == wl)
 		return (0);
 
-	if (session_alert_has_window(s, w, WINDOW_BELL))
-		return (0);
-	session_alert_add(s, w, WINDOW_BELL);
+	wl->flags |= WINLINK_BELL;
 
 	action = options_get_number(&s->options, "bell-action");
 	switch (action) {
@@ -155,25 +160,22 @@ server_window_check_bell(struct session *s, struct window *w)
 
 /* Check for activity in window. */
 int
-server_window_check_activity(struct session *s, struct window *w)
+server_window_check_activity(struct session *s, struct winlink *wl)
 {
 	struct client	*c;
+	struct window	*w = wl->window;
 	u_int		 i;
 
-	if (!(w->flags & WINDOW_ACTIVITY))
+	if (!(w->flags & WINDOW_ACTIVITY) || wl->flags & WINLINK_ACTIVITY)
 		return (0);
-	if (s->curw->window == w)
+	if (s->curw == wl)
 		return (0);
 
 	if (!options_get_number(&w->options, "monitor-activity"))
 		return (0);
 
-	if (session_alert_has_window(s, w, WINDOW_ACTIVITY))
-		return (0);
-	session_alert_add(s, w, WINDOW_ACTIVITY);
+	wl->flags |= WINLINK_ACTIVITY;
 
-	if (s->flags & SESSION_UNATTACHED)
-		return (0);
 	if (options_get_number(&s->options, "visual-activity")) {
 		for (i = 0; i < ARRAY_LENGTH(&clients); i++) {
 			c = ARRAY_ITEM(&clients, i);
@@ -190,31 +192,28 @@ server_window_check_activity(struct session *s, struct window *w)
 /* Check for content change in window. */
 int
 server_window_check_content(
-    struct session *s, struct window *w, struct window_pane *wp)
+    struct session *s, struct winlink *wl, struct window_pane *wp)
 {
 	struct client	*c;
+	struct window	*w = wl->window;
 	u_int		 i;
 	char		*found, *ptr;
 
-	if (!(w->flags & WINDOW_ACTIVITY))	/* activity for new content */
+	/* Activity flag must be set for new content. */
+	if (!(w->flags & WINDOW_ACTIVITY) || wl->flags & WINLINK_CONTENT)
 		return (0);
-	if (s->curw->window == w)
+	if (s->curw == wl)
 		return (0);
 
 	ptr = options_get_string(&w->options, "monitor-content");
 	if (ptr == NULL || *ptr == '\0')
 		return (0);
-
-	if (session_alert_has_window(s, w, WINDOW_CONTENT))
-		return (0);
-
 	if ((found = window_pane_search(wp, ptr, NULL)) == NULL)
 		return (0);
 	xfree(found);
 
-	session_alert_add(s, w, WINDOW_CONTENT);
-	if (s->flags & SESSION_UNATTACHED)
-		return (0);
+	wl->flags |= WINLINK_CONTENT;
+
 	if (options_get_number(&s->options, "visual-content")) {
 		for (i = 0; i < ARRAY_LENGTH(&clients); i++) {
 			c = ARRAY_ITEM(&clients, i);
diff --git a/session.c b/session.c
index 2957c1fc..65f8ef41 100644
--- a/session.c
+++ b/session.c
@@ -32,71 +32,8 @@ struct sessions	sessions;
 struct sessions dead_sessions;
 struct session_groups session_groups;
 
-struct winlink *session_next_alert(struct session *, struct winlink *);
-struct winlink *session_previous_alert(struct session *, struct winlink *);
-
-void
-session_alert_cancel(struct session *s, struct winlink *wl)
-{
-	struct session_alert	*sa, *sb;
-
-	sa = SLIST_FIRST(&s->alerts);
-	while (sa != NULL) {
-		sb = sa;
-		sa = SLIST_NEXT(sa, entry);
-
-		if (wl == NULL || sb->wl == wl) {
-			SLIST_REMOVE(&s->alerts, sb, session_alert, entry);
-			xfree(sb);
-		}
-	}
-}
-
-void
-session_alert_add(struct session *s, struct window *w, int type)
-{
-	struct session_alert	*sa;
-	struct winlink		*wl;
-
-	RB_FOREACH(wl, winlinks, &s->windows) {
-		if (wl == s->curw)
-			continue;
-
-		if (wl->window == w &&
-		    !session_alert_has(s, wl, type)) {
-			sa = xmalloc(sizeof *sa);
-			sa->wl = wl;
-			sa->type = type;
-			SLIST_INSERT_HEAD(&s->alerts, sa, entry);
-		}
-	}
-}
-
-int
-session_alert_has(struct session *s, struct winlink *wl, int type)
-{
-	struct session_alert	*sa;
-
-	SLIST_FOREACH(sa, &s->alerts, entry) {
-		if (sa->wl == wl && sa->type == type)
-			return (1);
-	}
-
-	return (0);
-}
-
-int
-session_alert_has_window(struct session *s, struct window *w, int type)
-{
-	struct session_alert	*sa;
-
-	SLIST_FOREACH(sa, &s->alerts, entry) {
-		if (sa->wl->window == w && sa->type == type)
-			return (1);
-	}
-
-	return (0);
-}
+struct winlink *session_next_alert(struct winlink *);
+struct winlink *session_previous_alert(struct winlink *);
 
 /* Find session by name. */
 struct session *
@@ -134,7 +71,6 @@ session_create(const char *name, const char *cmd, const char *cwd,
 	s->curw = NULL;
 	TAILQ_INIT(&s->lastw);
 	RB_INIT(&s->windows);
-	SLIST_INIT(&s->alerts);
 
 	paste_init_stack(&s->buffers);
 
@@ -197,7 +133,6 @@ session_destroy(struct session *s)
 		xfree(s->tio);
 
 	session_group_remove(s);
-	session_alert_cancel(s, NULL);
 	environ_free(&s->environ);
 	options_free(&s->options);
 	paste_free_stack(&s->buffers);
@@ -285,7 +220,7 @@ session_detach(struct session *s, struct winlink *wl)
 	    session_last(s) != 0 && session_previous(s, 0) != 0)
 		session_next(s, 0);
 
-	session_alert_cancel(s, wl);
+	wl->flags &= ~WINLINK_ALERTFLAGS;
 	winlink_stack_remove(&s->lastw, wl);
 	winlink_remove(&s->windows, wl);
 	session_group_synchronize_from(s);
@@ -297,27 +232,23 @@ session_detach(struct session *s, struct winlink *wl)
 }
 
 /* Return if session has window. */
-int
+struct winlink *
 session_has(struct session *s, struct window *w)
 {
 	struct winlink	*wl;
 
 	RB_FOREACH(wl, winlinks, &s->windows) {
 		if (wl->window == w)
-			return (1);
+			return (wl);
 	}
-	return (0);
+	return (NULL);
 }
 
 struct winlink *
-session_next_alert(struct session *s, struct winlink *wl)
+session_next_alert(struct winlink *wl)
 {
 	while (wl != NULL) {
-		if (session_alert_has(s, wl, WINDOW_BELL))
-			break;
-		if (session_alert_has(s, wl, WINDOW_ACTIVITY))
-			break;
-		if (session_alert_has(s, wl, WINDOW_CONTENT))
+		if (wl->flags & WINLINK_ALERTFLAGS)
 			break;
 		wl = winlink_next(wl);
 	}
@@ -335,10 +266,10 @@ session_next(struct session *s, int alert)
 
 	wl = winlink_next(s->curw);
 	if (alert)
-		wl = session_next_alert(s, wl);
+		wl = session_next_alert(wl);
 	if (wl == NULL) {
 		wl = RB_MIN(winlinks, &s->windows);
-		if (alert && ((wl = session_next_alert(s, wl)) == NULL))
+		if (alert && ((wl = session_next_alert(wl)) == NULL))
 			return (-1);
 	}
 	if (wl == s->curw)
@@ -346,19 +277,15 @@ session_next(struct session *s, int alert)
 	winlink_stack_remove(&s->lastw, wl);
 	winlink_stack_push(&s->lastw, s->curw);
 	s->curw = wl;
-	session_alert_cancel(s, wl);
+	wl->flags &= ~WINLINK_ALERTFLAGS;
 	return (0);
 }
 
 struct winlink *
-session_previous_alert(struct session *s, struct winlink *wl)
+session_previous_alert(struct winlink *wl)
 {
 	while (wl != NULL) {
-		if (session_alert_has(s, wl, WINDOW_BELL))
-			break;
-		if (session_alert_has(s, wl, WINDOW_ACTIVITY))
-			break;
-		if (session_alert_has(s, wl, WINDOW_CONTENT))
+		if (wl->flags & WINLINK_ALERTFLAGS)
 			break;
 		wl = winlink_previous(wl);
 	}
@@ -376,10 +303,10 @@ session_previous(struct session *s, int alert)
 
 	wl = winlink_previous(s->curw);
 	if (alert)
-		wl = session_previous_alert(s, wl);
+		wl = session_previous_alert(wl);
 	if (wl == NULL) {
 		wl = RB_MAX(winlinks, &s->windows);
-		if (alert && (wl = session_previous_alert(s, wl)) == NULL)
+		if (alert && (wl = session_previous_alert(wl)) == NULL)
 			return (-1);
 	}
 	if (wl == s->curw)
@@ -387,7 +314,7 @@ session_previous(struct session *s, int alert)
 	winlink_stack_remove(&s->lastw, wl);
 	winlink_stack_push(&s->lastw, s->curw);
 	s->curw = wl;
-	session_alert_cancel(s, wl);
+	wl->flags &= ~WINLINK_ALERTFLAGS;
 	return (0);
 }
 
@@ -405,7 +332,7 @@ session_select(struct session *s, int idx)
 	winlink_stack_remove(&s->lastw, wl);
 	winlink_stack_push(&s->lastw, s->curw);
 	s->curw = wl;
-	session_alert_cancel(s, wl);
+	wl->flags &= ~WINLINK_ALERTFLAGS;
 	return (0);
 }
 
@@ -424,7 +351,7 @@ session_last(struct session *s)
 	winlink_stack_remove(&s->lastw, wl);
 	winlink_stack_push(&s->lastw, s->curw);
 	s->curw = wl;
-	session_alert_cancel(s, wl);
+	wl->flags &= ~WINLINK_ALERTFLAGS;
 	return (0);
 }
 
@@ -541,7 +468,6 @@ session_group_synchronize1(struct session *target, struct session *s)
 	struct winlinks		 old_windows, *ww;
 	struct winlink_stack	 old_lastw;
 	struct winlink		*wl, *wl2;
-	struct session_alert	*sa;
 
 	/* Don't do anything if the session is empty (it'll be destroyed). */
 	ww = &target->windows;
@@ -559,8 +485,10 @@ session_group_synchronize1(struct session *target, struct session *s)
 	RB_INIT(&s->windows);
 
 	/* Link all the windows from the target. */
-	RB_FOREACH(wl, winlinks, ww)
-		winlink_add(&s->windows, wl->window, wl->idx);
+	RB_FOREACH(wl, winlinks, ww) {
+		wl2 = winlink_add(&s->windows, wl->window, wl->idx);
+		wl2->flags |= wl->flags & WINLINK_ALERTFLAGS;
+	}
 
 	/* Fix up the current window. */
 	if (s->curw != NULL)
@@ -577,15 +505,6 @@ session_group_synchronize1(struct session *target, struct session *s)
 			TAILQ_INSERT_TAIL(&s->lastw, wl2, sentry);
 	}
 
-	/* And update the alerts list. */
-	SLIST_FOREACH(sa, &s->alerts, entry) {
-		wl = winlink_find_by_index(&s->windows, sa->wl->idx);
-		if (wl == NULL)
-			session_alert_cancel(s, sa->wl);
-		else
-			sa->wl = wl;
-	}
-
 	/* Then free the old winlinks list. */
 	while (!RB_EMPTY(&old_windows)) {
 		wl = RB_ROOT(&old_windows);
diff --git a/status.c b/status.c
index 4399ae43..b1d93c97 100644
--- a/status.c
+++ b/status.c
@@ -248,25 +248,15 @@ status_redraw(struct client *c)
 	 */
 	offset = 0;
 	RB_FOREACH(wl, winlinks, &s->windows) {
-		if (larrow == 1 && offset < wlstart) {
-			if (session_alert_has(s, wl, WINDOW_ACTIVITY))
-				larrow = -1;
-			else if (session_alert_has(s, wl, WINDOW_BELL))
-				larrow = -1;
-			else if (session_alert_has(s, wl, WINDOW_CONTENT))
-				larrow = -1;
-		}
+		if (wl->flags & WINLINK_ALERTFLAGS &&
+		    larrow == 1 && offset < wlstart)
+			larrow = -1;
 
 		offset += wl->status_width;
 
-		if (rarrow == 1 && offset > wlstart + wlwidth) {
-			if (session_alert_has(s, wl, WINDOW_ACTIVITY))
-				rarrow = -1;
-			else if (session_alert_has(s, wl, WINDOW_BELL))
-				rarrow = -1;
-			else if (session_alert_has(s, wl, WINDOW_CONTENT))
-				rarrow = -1;
-		}
+		if (wl->flags & WINLINK_ALERTFLAGS &&
+		    rarrow == 1 && offset > wlstart + wlwidth)
+			rarrow = -1;
 	}
 
 draw:
@@ -399,11 +389,11 @@ status_replace1(struct client *c,struct winlink *wl,
 		goto do_replace;
 	case 'F':
 		tmp[0] = ' ';
-		if (session_alert_has(s, wl, WINDOW_CONTENT))
+		if (wl->flags & WINLINK_CONTENT)
 			tmp[0] = '+';
-		else if (session_alert_has(s, wl, WINDOW_BELL))
+		else if (wl->flags & WINLINK_BELL)
 			tmp[0] = '!';
-		else if (session_alert_has(s, wl, WINDOW_ACTIVITY))
+		else if (wl->flags & WINLINK_ACTIVITY)
 			tmp[0] = '#';
 		else if (wl == s->curw)
 			tmp[0] = '*';
@@ -593,9 +583,7 @@ status_print(
 		fmt = options_get_string(oo, "window-status-current-format");
 	}
 
-	if (session_alert_has(s, wl, WINDOW_ACTIVITY) ||
-	    session_alert_has(s, wl, WINDOW_BELL) ||
-	    session_alert_has(s, wl, WINDOW_CONTENT)) {
+	if (wl->flags & WINLINK_ALERTFLAGS) {
 		fg = options_get_number(oo, "window-status-alert-fg");
 		if (fg != 8)
 			colour_set_fg(gc, fg);
diff --git a/tmux.h b/tmux.h
index c090aedd..10f3e593 100644
--- a/tmux.h
+++ b/tmux.h
@@ -843,8 +843,7 @@ struct window {
 #define WINDOW_BELL 0x1
 #define WINDOW_HIDDEN 0x2
 #define WINDOW_ACTIVITY 0x4
-#define WINDOW_CONTENT 0x8
-#define WINDOW_REDRAW 0x10
+#define WINDOW_REDRAW 0x8
 
 	struct options	 options;
 
@@ -861,6 +860,12 @@ struct winlink {
 	struct grid_cell status_cell;
 	char		*status_text;
 
+	int              flags;
+#define WINLINK_BELL 0x1
+#define WINLINK_ACTIVITY 0x2
+#define WINLINK_CONTENT 0x4
+#define WINLINK_ALERTFLAGS (WINLINK_BELL|WINLINK_ACTIVITY|WINLINK_CONTENT)
+
 	RB_ENTRY(winlink) entry;
 	TAILQ_ENTRY(winlink) sentry;
 };
@@ -912,13 +917,6 @@ struct environ_entry {
 RB_HEAD(environ, environ_entry);
 
 /* Client session. */
-struct session_alert {
-	struct winlink	*wl;
-	int		 type;
-
-	SLIST_ENTRY(session_alert) entry;
-};
-
 struct session_group {
 	TAILQ_HEAD(, session) sessions;
 
@@ -943,8 +941,6 @@ struct session {
 
 	struct paste_stack buffers;
 
-	SLIST_HEAD(, session_alert) alerts;
-
 #define SESSION_UNATTACHED 0x1	/* not attached to any clients */
 #define SESSION_DEAD 0x2
 	int		 flags;
@@ -1911,10 +1907,6 @@ void clear_signals(void);
 extern struct sessions sessions;
 extern struct sessions dead_sessions;
 extern struct session_groups session_groups;
-void	 session_alert_add(struct session *, struct window *, int);
-void	 session_alert_cancel(struct session *, struct winlink *);
-int	 session_alert_has(struct session *, struct winlink *, int);
-int	 session_alert_has_window(struct session *, struct window *, int);
 struct session	*session_find(const char *);
 struct session	*session_create(const char *, const char *, const char *,
 		     struct environ *, struct termios *, int, u_int, u_int,
@@ -1926,7 +1918,7 @@ struct winlink	*session_new(struct session *,
 struct winlink	*session_attach(
 		     struct session *, struct window *, int, char **);
 int		 session_detach(struct session *, struct winlink *);
-int		 session_has(struct session *, struct window *);
+struct winlink*	 session_has(struct session *, struct window *);
 int		 session_next(struct session *, int);
 int		 session_previous(struct session *, int);
 int		 session_select(struct session *, int);