diff -paur xchat2.orig/src/common/inbound.c xchat2/src/common/inbound.c
--- xchat2.orig/src/common/inbound.c	2008-07-20 17:31:44.898468115 +0200
+++ xchat2/src/common/inbound.c	2008-07-19 19:57:09.799906780 +0200
@@ -297,7 +297,10 @@ is_hilight (char *from, char *text, sess
 	{
 		g_free (text);
 		if (sess != current_tab)
+		{
 			sess->nick_said = TRUE;
+			lastact_update(sess);
+		}
 		fe_set_hilight (sess);
 		return 1;
 	}
@@ -344,6 +347,7 @@ inbound_action (session *sess, char *cha
 			sess->msg_said = TRUE;
 			sess->new_data = FALSE;
 		}
+		lastact_update(sess);
 	}
 
 	user = userlist_find (sess, from);
@@ -395,6 +399,7 @@ inbound_chanmsg (server *serv, session *
 	{
 		sess->msg_said = TRUE;
 		sess->new_data = FALSE;
+		lastact_update(sess);
 	}
 
 	user = userlist_find (sess, from);
diff -paur xchat2.orig/src/common/xchat.c xchat2/src/common/xchat.c
--- xchat2.orig/src/common/xchat.c	2008-07-20 17:31:44.900468825 +0200
+++ xchat2/src/common/xchat.c	2008-07-20 17:33:57.089468218 +0200
@@ -71,6 +71,23 @@ GSList *usermenu_list = 0;
 GSList *urlhandler_list = 0;
 GSList *tabmenu_list = 0;
 
+/*
+ * This array contains 5 double linked lists, one for each priority in the
+ * "interesting session" queue ("channel" stands for everything but
+ * SESS_DIALOG):
+ *
+ * [0] queries with hilight
+ * [1] queries
+ * [2] channels with hilight
+ * [3] channels with dialogue
+ * [4] channels with other data
+ *
+ * Each time activity happens the corresponding session is put at the
+ * beginning of one of the lists.  The aim is to be able to switch to the
+ * session with the most important/recent activity.
+ */
+GList *sess_list_by_lastact[5] = {NULL, NULL, NULL, NULL, NULL};
+
 static int in_xchat_exit = FALSE;
 int xchat_is_quitting = FALSE;
 /* command-line args */
@@ -93,6 +110,105 @@ struct xchatprefs prefs;
 SSL_CTX *ctx = NULL;
 #endif
 
+/*
+ * Update the priority queue of the "interesting sessions"
+ * (sess_list_by_lastact).
+ */
+void
+lastact_update(session *sess)
+{
+	int newidx;
+
+	/* Find the priority (for the order see before) */
+	if (sess->type == SESS_DIALOG)
+	{
+		if (sess->nick_said)
+			newidx = LACT_QUERY_HI;
+		else if (sess->msg_said)
+			newidx = LACT_QUERY;
+		else if (sess->new_data)
+			newidx = LACT_QUERY;
+		else
+			newidx = LACT_NONE;
+	}
+	else
+	{
+		if (sess->nick_said)
+			newidx = LACT_CHAN_HI;
+		else if (sess->msg_said)
+			newidx = LACT_CHAN;
+		else if (sess->new_data)
+			newidx = LACT_CHAN_DATA;
+		else
+			newidx = LACT_NONE;
+	}
+
+	/* Check if this update is a no-op */
+	if (sess->lastact_idx == newidx && 
+			((newidx != LACT_NONE && sess->lastact_elem == sess_list_by_lastact[newidx]) ||
+			 (newidx == LACT_NONE)))
+		return;
+
+	/* Remove from the old position (and, if no new position, return */
+	else if (sess->lastact_idx != LACT_NONE && sess->lastact_elem)
+	{
+		sess_list_by_lastact[sess->lastact_idx] = g_list_remove_link(
+				sess_list_by_lastact[sess->lastact_idx],
+				sess->lastact_elem);
+		if (newidx == LACT_NONE)
+		{
+			sess->lastact_idx = newidx;
+			return;
+		}
+	}
+
+	/* No previous position, allocate new */
+	else if (!sess->lastact_elem)
+		sess->lastact_elem = g_list_prepend(sess->lastact_elem, sess);
+
+	sess->lastact_idx = newidx;
+	sess_list_by_lastact[newidx] = g_list_concat(
+			sess->lastact_elem, sess_list_by_lastact[newidx]);
+}
+
+/*
+ * Extract the first session from the priority queue of sessions with recent
+ * activity. Return NULL if no such session can be found.
+ *
+ * If filter is specified, skip a session if filter(session) returns 0. This
+ * can be used for UI-specific needs, e.g. in fe-gtk we want to filter out
+ * detached sessions.
+ */
+session *
+lastact_getfirst(int (*filter) (session *sess))
+{
+	int i;
+	session *sess = NULL;
+	GList *curitem;
+
+	/* 5 is the number of priority classes LACT_ */
+	for (i = 0; i < 5 && !sess; i++)
+	{
+		curitem = sess_list_by_lastact[i];
+		while (curitem && !sess)
+		{
+			sess = g_list_nth_data(curitem, 0);
+			if (!sess || (filter && !filter(sess)))
+			{
+				sess = NULL;
+				curitem = g_list_next(curitem);
+			}
+		}
+
+		if (sess)
+		{
+			sess_list_by_lastact[i] = g_list_remove_link(sess_list_by_lastact[i], curitem);
+			sess->lastact_idx = LACT_NONE;
+		}
+	}
+	
+	return sess;
+}
 
 int
 is_session (session * sess)
@@ -362,6 +478,9 @@ session_new (server *serv, char *from, i
 
 	sess_list = g_slist_prepend (sess_list, sess);
 
+	sess->lastact_elem = NULL;
+	sess->lastact_idx = LACT_NONE;
+
 	fe_new_window (sess, focus);
 
 	return sess;
@@ -533,6 +652,16 @@ session_free (session *killsess)
 			current_sess = sess_list->data;
 	}
 
+	if (killsess->lastact_elem)
+	{
+		if (killsess->lastact_idx != LACT_NONE)
+			sess_list_by_lastact[killsess->lastact_idx] = g_list_delete_link(
+					sess_list_by_lastact[killsess->lastact_idx],
+					killsess->lastact_elem);
+		else
+			g_list_free_1(killsess->lastact_elem);
+	}
+
 	free (killsess);
 
 	if (!sess_list && !in_xchat_exit)
diff -paur xchat2.orig/src/common/xchat.h xchat2/src/common/xchat.h
--- xchat2.orig/src/common/xchat.h	2008-07-20 17:31:44.901467675 +0200
+++ xchat2/src/common/xchat.h	2008-07-20 17:33:28.240467970 +0200
@@ -320,6 +320,15 @@ struct xchatprefs
 #define SET_ON 1
 #define SET_DEFAULT 2 /* use global setting */
 
+/* Priorities in the "interesting sessions" priority queue
+ * (see xchat.c:sess_list_by_lastact) */
+#define LACT_NONE		-1		/* no queues */
+#define LACT_QUERY_HI	0		/* query with hilight */
+#define LACT_QUERY		1		/* query with messages */
+#define LACT_CHAN_HI	2		/* channel with hilight */
+#define LACT_CHAN		3		/* channel with messages */
+#define LACT_CHAN_DATA	4		/* channel with other data */
+
 typedef struct session
 {
 	/* Per-Channel Alerts */
@@ -369,6 +378,10 @@ typedef struct session
 
 	int type;					/* SESS_* */
 
+	GList *lastact_elem;	/* our GList element in sess_list_by_lastact */
+	int lastact_idx;		/* the sess_list_by_lastact[] index of the list we're in.
+							 * For valid values, see defines of LACT_*. */
+
 	int new_data:1;			/* new data avail? (purple tab) */
 	int nick_said:1;		/* your nick mentioned? (blue tab) */
 	int msg_said:1;			/* new msg available? (red tab) */
diff -paur xchat2.orig/src/common/xchatc.h xchat2/src/common/xchatc.h
--- xchat2.orig/src/common/xchatc.h	2008-07-20 17:31:44.901467675 +0200
+++ xchat2/src/common/xchatc.h	2008-07-20 11:43:36.673967630 +0200
@@ -25,10 +25,13 @@ extern GSList *ignore_list;
 extern GSList *usermenu_list;
 extern GSList *urlhandler_list;
 extern GSList *tabmenu_list;
+extern GList *sess_list_by_lastact[];
 
 session * find_channel (server *serv, char *chan);
 session * find_dialog (server *serv, char *nick);
 session * new_ircwindow (server *serv, char *name, int type, int focus);
+void lastact_update (session * sess);
+session * lastact_getfirst (int (*filter) (session *sess));
 int is_session (session * sess);
 void session_free (session *killsess);
 void lag_check (void);
diff -paur xchat2.orig/src/fe-gtk/fe-gtk.c xchat2/src/fe-gtk/fe-gtk.c
--- xchat2.orig/src/fe-gtk/fe-gtk.c	2008-07-20 17:31:44.958466232 +0200
+++ xchat2/src/fe-gtk/fe-gtk.c	2008-07-19 19:58:57.431961788 +0200
@@ -603,6 +603,7 @@ fe_print_text (struct session *sess, cha
 		 sess->gui->is_tab && !sess->nick_said && stamp == 0)
 	{
 		sess->new_data = TRUE;
+		lastact_update(sess);
 		if (sess->msg_said)
 			fe_set_tab_color (sess, 2);
 		else
diff -paur xchat2.orig/src/fe-gtk/fkeys.c xchat2/src/fe-gtk/fkeys.c
--- xchat2.orig/src/fe-gtk/fkeys.c	2008-07-20 17:31:44.960465847 +0200
+++ xchat2/src/fe-gtk/fkeys.c	2008-07-20 12:20:50.186930065 +0200
@@ -158,7 +158,7 @@ static const struct key_action key_actio
 	{key_action_handle_command, "Run Command",
 	 N_("The \002Run Command\002 action runs the data in Data 1 as if it has been typed into the entry box where you pressed the key sequence. Thus it can contain text (which will be sent to the channel/person), commands or user commands. When run all \002\\n\002 characters in Data 1 are used to deliminate seperate commands so it is possible to run more than one command. If you want a \002\\\002 in the actual text run then enter \002\\\\\002")},
 	{key_action_page_switch, "Change Page",
-	 N_("The \002Change Page\002 command switches between pages in the notebook. Set Data 1 to the page you want to switch to. If Data 2 is set to anything then the switch will be relative to the current position")},
+	 N_("The \002Change Page\002 command switches between pages in the notebook. Set Data 1 to the page you want to switch to. If Data 2 is set to anything then the switch will be relative to the current position. Set Data 1 to auto to switch to the page with the most recent and important activity (queries first, then channels with hilight, channels with dialogue, channels with other data)")},
 	{key_action_insert, "Insert in Buffer",
 	 N_("The \002Insert in Buffer\002 command will insert the contents of Data 1 into the entry where the key sequence was pressed at the current cursor position")},
 	{key_action_scroll_page, "Scroll Page",
@@ -402,6 +402,7 @@ key_load_defaults ()
 		"A\n3\nChange Page\nD1:3\nD2!\n\n"\
 		"A\n2\nChange Page\nD1:2\nD2!\n\n"\
 		"A\n1\nChange Page\nD1:1\nD2!\n\n"\
+		"A\ngrave\nChange Page\nD1:auto\nD2!\n\n"\
 		"C\no\nInsert in Buffer\nD1:\nD2!\n\n"\
 		"C\nb\nInsert in Buffer\nD1:\nD2!\n\n"\
 		"C\nk\nInsert in Buffer\nD1:\nD2!\n\n"\
@@ -1196,6 +1197,20 @@ key_action_handle_command (GtkWidget * w
 	return 0;
 }
 
+/*
+ * Check if the given session is inside the main window. This predicate
+ * is passed to lastact_pop as a way to filter out detached sessions.
+ * XXX: Consider moving this in a different file?
+ */
+static int
+session_check_is_tab(session *sess)
+{
+	if (!sess || !sess->gui)
+		return FALSE;
+
+	return (sess->gui->is_tab);
+}
+
 static int
 key_action_page_switch (GtkWidget * wid, GdkEventKey * evt, char *d1,
 								char *d2, struct session *sess)
@@ -1209,6 +1224,30 @@ key_action_page_switch (GtkWidget * wid,
 	if (!len)
 		return 1;
 
+	if (strcasecmp(d1, "auto") == 0)
+	{
+		/* Auto switch makes no sense in detached sessions */
+		if (!sess->gui->is_tab)
+			return 1;
+
+		/* Obtain a session with recent activity */
+		session *newsess = lastact_getfirst(session_check_is_tab);
+
+		if (newsess)
+		{
+			/*
+			 * Only sessions in the current window should be considered (i.e.
+			 * we don't want to move the focus on a different window). This
+			 * call could, in theory, do this, but we checked before that
+			 * newsess->gui->is_tab and sess->gui->is_tab.
+			 */
+			mg_bring_tofront_sess(newsess);
+			return 0;
+		}
+		else
+			return 1;
+	}
+
 	for (i = 0; i < len; i++)
 	{
 		if (d1[i] < '0' || d1[i] > '9')
diff -paur xchat2.orig/src/fe-gtk/maingui.c xchat2/src/fe-gtk/maingui.c
--- xchat2.orig/src/fe-gtk/maingui.c	2008-07-20 17:31:44.964469466 +0200
+++ xchat2/src/fe-gtk/maingui.c	2008-07-19 19:58:58.255909127 +0200
@@ -359,6 +359,7 @@ fe_set_tab_color (struct session *sess, 
 				
 			break;
 		}
+		lastact_update(sess);
 	}
 }
 
@@ -643,6 +644,7 @@ mg_focus (session *sess)
 		sess->nick_said = FALSE;
 		sess->msg_said = FALSE;
 		sess->new_data = FALSE;
+		lastact_update(sess);
 		/* when called via mg_changui_new, is_tab might be true, but
 			sess->res->tab is still NULL. */
 		if (sess->res->tab)