diff --git a/Makefile b/Makefile
index dd2e4e98..2e23b71a 100644
--- a/Makefile
+++ b/Makefile
@@ -31,7 +31,7 @@ SRCS=	arguments.c attributes.c cfg.c client.c clock.c \
 	cmd-pipe-pane.c cmd-capture-pane.c cmd.c \
 	colour.c environ.c grid-view.c grid-utf8.c grid.c input-keys.c \
 	input.c key-bindings.c key-string.c format.c \
-	layout-custom.c layout-set.c layout.c log.c job.c \
+	layout-custom.c layout-set.c layout.c log.c job.c notify.c \
 	mode-key.c names.c options.c options-table.c paste.c procname.c \
 	resize.c screen-redraw.c screen-write.c screen.c session.c status.c \
 	signal.c server-fn.c server.c server-client.c server-window.c \
diff --git a/cmd-attach-session.c b/cmd-attach-session.c
index 18e06323..bdf3568e 100644
--- a/cmd-attach-session.c
+++ b/cmd-attach-session.c
@@ -74,6 +74,7 @@ cmd_attach_session_exec(struct cmd *self, struct cmd_ctx *ctx)
 		}
 
 		ctx->curclient->session = s;
+		notify_attached_session_changed(ctx->curclient);
 		session_update_activity(s);
 		server_redraw_client(ctx->curclient);
 		s->curw->flags &= ~WINLINK_ALERTFLAGS;
@@ -98,6 +99,7 @@ cmd_attach_session_exec(struct cmd *self, struct cmd_ctx *ctx)
 			server_write_session(s, MSG_DETACH, NULL, 0);
 
 		ctx->cmdclient->session = s;
+		notify_attached_session_changed(ctx->cmdclient);
 		session_update_activity(s);
 		server_write_client(ctx->cmdclient, MSG_READY, NULL, 0);
 
diff --git a/cmd-join-pane.c b/cmd-join-pane.c
index 03fb4317..dedda5ef 100644
--- a/cmd-join-pane.c
+++ b/cmd-join-pane.c
@@ -148,6 +148,8 @@ join_pane(struct cmd *self, struct cmd_ctx *ctx, int not_same_window)
 
 	if (window_count_panes(src_w) == 0)
 		server_kill_window(src_w);
+	else
+		notify_window_layout_changed(src_w);
 
 	src_wp->window = dst_w;
 	TAILQ_INSERT_AFTER(&dst_w->panes, dst_wp, src_wp, entry);
@@ -165,5 +167,6 @@ join_pane(struct cmd *self, struct cmd_ctx *ctx, int not_same_window)
 	} else
 		server_status_session(dst_s);
 
+	notify_window_layout_changed(dst_w);
 	return (0);
 }
diff --git a/cmd-new-session.c b/cmd-new-session.c
index 5fb9e62c..d40b5095 100644
--- a/cmd-new-session.c
+++ b/cmd-new-session.c
@@ -244,6 +244,7 @@ cmd_new_session_exec(struct cmd *self, struct cmd_ctx *ctx)
 			if (old_s != NULL)
 				ctx->cmdclient->last_session = old_s;
 			ctx->cmdclient->session = s;
+			notify_attached_session_changed(ctx->cmdclient);
 			session_update_activity(s);
 			server_redraw_client(ctx->cmdclient);
 		} else {
@@ -251,6 +252,7 @@ cmd_new_session_exec(struct cmd *self, struct cmd_ctx *ctx)
 			if (old_s != NULL)
 				ctx->curclient->last_session = old_s;
 			ctx->curclient->session = s;
+			notify_attached_session_changed(ctx->curclient);
 			session_update_activity(s);
 			server_redraw_client(ctx->curclient);
 		}
diff --git a/cmd-new-window.c b/cmd-new-window.c
index c906d4d2..5051ab1a 100644
--- a/cmd-new-window.c
+++ b/cmd-new-window.c
@@ -89,6 +89,7 @@ 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.
 		 */
+		notify_window_unlinked(s, wl->window);
 		wl->flags &= ~WINLINK_ALERTFLAGS;
 		winlink_stack_remove(&s->lastw, wl);
 		winlink_remove(&s->windows, wl);
diff --git a/cmd-rename-session.c b/cmd-rename-session.c
index cbda700f..9f741d8d 100644
--- a/cmd-rename-session.c
+++ b/cmd-rename-session.c
@@ -64,6 +64,7 @@ cmd_rename_session_exec(struct cmd *self, struct cmd_ctx *ctx)
 	RB_INSERT(sessions, &sessions, s);
 
 	server_status_session(s);
+	notify_session_renamed(s);
 
 	return (0);
 }
diff --git a/cmd-split-window.c b/cmd-split-window.c
index 08a371c9..5123942e 100644
--- a/cmd-split-window.c
+++ b/cmd-split-window.c
@@ -156,6 +156,7 @@ cmd_split_window_exec(struct cmd *self, struct cmd_ctx *ctx)
 
 		format_free(ft);
 	}
+	notify_window_layout_changed(w);
 	return (0);
 
 error:
diff --git a/layout-custom.c b/layout-custom.c
index 8a4f08dc..dbbb8c14 100644
--- a/layout-custom.c
+++ b/layout-custom.c
@@ -172,6 +172,8 @@ layout_parse(struct window *w, const char *layout)
 
 	layout_print_cell(lc, __func__, 0);
 
+	notify_window_layout_changed(w);
+
 	return (0);
 
 fail:
diff --git a/layout.c b/layout.c
index 1050efc4..4e51a594 100644
--- a/layout.c
+++ b/layout.c
@@ -483,6 +483,7 @@ layout_resize_pane(struct window_pane *wp, enum layout_type type, int change)
 	/* Fix cell offsets. */
 	layout_fix_offsets(wp->window->layout_root);
 	layout_fix_panes(wp->window, wp->window->sx, wp->window->sy);
+	notify_window_layout_changed(wp->window);
 }
 
 void
@@ -742,4 +743,5 @@ layout_close_pane(struct window_pane *wp)
 		layout_fix_offsets(wp->window->layout_root);
 		layout_fix_panes(wp->window, wp->window->sx, wp->window->sy);
 	}
+	notify_window_layout_changed(wp->window);
 }
diff --git a/notify.c b/notify.c
new file mode 100644
index 00000000..a9d89ee5
--- /dev/null
+++ b/notify.c
@@ -0,0 +1,59 @@
+/* $OpenBSD$ */
+
+/*
+ * Copyright (c) 2012 George Nachman <tmux@georgester.com>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF MIND, USE, DATA OR PROFITS, WHETHER
+ * IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
+ * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include "tmux.h"
+
+void
+notify_window_layout_changed(unused struct window *w)
+{
+}
+
+void
+notify_window_unlinked(unused struct session *s, unused struct window *w)
+{
+}
+
+void
+notify_window_linked(unused struct session *s, unused struct window *w)
+{
+}
+
+void
+notify_window_renamed(unused struct window *w)
+{
+}
+
+void
+notify_attached_session_changed(unused struct client *c)
+{
+}
+
+void
+notify_session_renamed(unused struct session *s)
+{
+}
+
+void
+notify_session_created(unused struct session *s)
+{
+}
+
+void
+notify_session_closed(unused struct session *s)
+{
+}
diff --git a/resize.c b/resize.c
index 517a7481..5553ce9a 100644
--- a/resize.c
+++ b/resize.c
@@ -141,5 +141,6 @@ recalculate_sizes(void)
 		}
 
 		server_redraw_window(w);
+		notify_window_layout_changed(w);
 	}
 }
diff --git a/server-fn.c b/server-fn.c
index 66298571..f6b1cb7a 100644
--- a/server-fn.c
+++ b/server-fn.c
@@ -293,6 +293,7 @@ server_link_window(struct session *src, struct winlink *srcwl,
 			 * Can't use session_detach as it will destroy session
 			 * if this makes it empty.
 			 */
+			notify_window_unlinked(dst, dstwl->window);
 			dstwl->flags &= ~WINLINK_ALERTFLAGS;
 			winlink_stack_remove(&dst->lastw, dstwl);
 			winlink_remove(&dst->windows, dstwl);
@@ -419,6 +420,7 @@ server_destroy_session(struct session *s)
 		} else {
 			c->last_session = NULL;
 			c->session = s_new;
+			notify_attached_session_changed(c);
 			session_update_activity(s_new);
 			server_redraw_client(c);
 		}
diff --git a/session.c b/session.c
index 2545d868..0109fd5d 100644
--- a/session.c
+++ b/session.c
@@ -142,6 +142,7 @@ session_create(const char *name, const char *cmd, const char *cwd,
 	}
 
 	log_debug("session %s created", s->name);
+	notify_session_created(s);
 
 	return (s);
 }
@@ -150,9 +151,11 @@ session_create(const char *name, const char *cmd, const char *cwd,
 void
 session_destroy(struct session *s)
 {
+	struct winlink	*wl;
 	log_debug("session %s destroyed", s->name);
 
 	RB_REMOVE(sessions, &sessions, s);
+	notify_session_closed(s);
 
 	if (s->tio != NULL)
 		xfree(s->tio);
@@ -163,8 +166,11 @@ session_destroy(struct session *s)
 
 	while (!TAILQ_EMPTY(&s->lastw))
 		winlink_stack_remove(&s->lastw, TAILQ_FIRST(&s->lastw));
-	while (!RB_EMPTY(&s->windows))
-		winlink_remove(&s->windows, RB_ROOT(&s->windows));
+	while (!RB_EMPTY(&s->windows)) {
+		wl = RB_ROOT(&s->windows);
+		notify_window_unlinked(s, wl->window);
+		winlink_remove(&s->windows, wl);
+	}
 
 	xfree(s->cwd);
 
@@ -254,6 +260,7 @@ session_new(struct session *s,
 		return (NULL);
 	}
 	winlink_set_window(wl, w);
+	notify_window_linked(s, w);
 	environ_free(&env);
 
 	if (options_get_number(&s->options, "set-remain-on-exit"))
@@ -274,6 +281,7 @@ session_attach(struct session *s, struct window *w, int idx, char **cause)
 		return (NULL);
 	}
 	winlink_set_window(wl, w);
+	notify_window_linked(s, w);
 
 	session_group_synchronize_from(s);
 	return (wl);
@@ -288,6 +296,7 @@ session_detach(struct session *s, struct winlink *wl)
 		session_next(s, 0);
 
 	wl->flags &= ~WINLINK_ALERTFLAGS;
+	notify_window_unlinked(s, wl->window);
 	winlink_stack_remove(&s->lastw, wl);
 	winlink_remove(&s->windows, wl);
 	session_group_synchronize_from(s);
@@ -555,6 +564,7 @@ session_group_synchronize1(struct session *target, struct session *s)
 	RB_FOREACH(wl, winlinks, ww) {
 		wl2 = winlink_add(&s->windows, wl->idx);
 		winlink_set_window(wl2, wl->window);
+		notify_window_linked(s, wl2->window);
 		wl2->flags |= wl->flags & WINLINK_ALERTFLAGS;
 	}
 
@@ -576,6 +586,8 @@ session_group_synchronize1(struct session *target, struct session *s)
 	/* Then free the old winlinks list. */
 	while (!RB_EMPTY(&old_windows)) {
 		wl = RB_ROOT(&old_windows);
+		if (winlink_find_by_window_id(&s->windows, wl->window->id) == NULL)
+		    notify_window_unlinked(s, wl->window);
 		winlink_remove(&old_windows, wl);
 	}
 }
diff --git a/tmux.h b/tmux.h
index 9257117a..5f2f3a44 100644
--- a/tmux.h
+++ b/tmux.h
@@ -1396,6 +1396,16 @@ void	mode_key_init_trees(void);
 void	mode_key_init(struct mode_key_data *, struct mode_key_tree *);
 enum mode_key_cmd mode_key_lookup(struct mode_key_data *, int);
 
+/* notify.c */
+void	notify_window_layout_changed(struct window *);
+void	notify_window_unlinked(struct session *, struct window *);
+void	notify_window_linked(struct session *, struct window *);
+void	notify_window_renamed(struct window *);
+void	notify_attached_session_changed(struct client *);
+void	notify_session_renamed(struct session *);
+void	notify_session_created(struct session *);
+void	notify_session_closed(struct session *);
+
 /* options.c */
 int	options_cmp(struct options_entry *, struct options_entry *);
 RB_PROTOTYPE(options_tree, options_entry, entry, options_cmp);
diff --git a/window.c b/window.c
index f0061293..51d43ac4 100644
--- a/window.c
+++ b/window.c
@@ -368,6 +368,7 @@ window_set_name(struct window *w, const char *new_name)
 	if (w->name != NULL)
 		xfree(w->name);
 	w->name = xstrdup(new_name);
+	notify_window_renamed(w);
 }
 
 void