Changing source in CompEditor blocks UI

5 files changed, 289 insertions, 114 deletions

diff --git a/calendar/gui/dialogs/event-page.c b/calendar/gui/dialogs/event-page.c
index 12b59a2c32..0ecb18393c 100644
--- a/calendar/gui/dialogs/event-page.c
+++ b/calendar/gui/dialogs/event-page.c
@@ -192,6 +192,8 @@ struct _EventPagePrivate {
 
 	/* either with-user-time or without it */
 	const gint *alarm_map;
+
+	GCancellable *open_cancellable;
 };
 
 static void event_page_set_dates (CompEditorPage *page, CompEditorPageDates *dates);
@@ -867,6 +869,12 @@ event_page_dispose (GObject *object)
 
 	priv = EVENT_PAGE_GET_PRIVATE (object);
 
+	if (priv->open_cancellable) {
+		g_cancellable_cancel (priv->open_cancellable);
+		g_object_unref (priv->open_cancellable);
+		priv->open_cancellable = NULL;
+	}
+
 	if (priv->location_completion != NULL) {
 		g_object_unref (priv->location_completion);
 		priv->location_completion = NULL;
@@ -1794,6 +1802,7 @@ event_page_init (EventPage *epage)
 	epage->priv->alarm_interval = -1;
 	epage->priv->alarm_map = alarm_map_with_user_time;
 	epage->priv->location_completion = gtk_entry_completion_new ();
+	epage->priv->open_cancellable = NULL;
 }
 
 void
@@ -2849,39 +2858,31 @@ event_page_send_options_clicked_cb (EventPage *epage)
 }
 
 static void
-source_changed_cb (ESourceComboBox *source_combo_box, EventPage *epage)
+epage_client_opened_cb (GObject *source_object, GAsyncResult *result, gpointer user_data)
 {
-	EventPagePrivate *priv = epage->priv;
+	ESource *source = E_SOURCE (source_object);
+	EClient *client = NULL;
+	EventPage *epage = user_data;
+	EventPagePrivate *priv;
 	CompEditor *editor;
-	ESource *source;
-	ECalClient *client;
 	GError *error = NULL;
 
-	if (comp_editor_page_get_updating (COMP_EDITOR_PAGE (epage)))
-		return;
+	if (!e_client_utils_open_new_finish (source, result, &client, &error)) {
+		if (g_error_matches (error, E_CLIENT_ERROR, E_CLIENT_ERROR_CANCELLED) ||
+		    g_error_matches (error, G_IO_ERROR, G_IO_ERROR_CANCELLED)) {
+			return;
+		}
+	}
 
 	editor = comp_editor_page_get_editor (COMP_EDITOR_PAGE (epage));
-	source = e_source_combo_box_get_active (source_combo_box);
-	client = e_cal_client_new (source, E_CAL_CLIENT_SOURCE_TYPE_EVENTS, &error);
-
-	if (client) {
-		icaltimezone *zone;
-
-		zone = e_meeting_store_get_timezone (epage->priv->meeting_store);
-		e_cal_client_set_default_timezone (client, zone);
-
-		g_signal_connect (client, "authenticate", G_CALLBACK (e_client_utils_authenticate_handler), NULL);
-	}
+	priv = epage->priv;
 
-	if (!client || !e_client_open_sync (E_CLIENT (client), FALSE, NULL, &error)) {
+	if (error) {
 		GtkWidget *dialog;
 		ECalClient *old_client;
 
 		old_client = comp_editor_get_client (editor);
 
-		if (client)
-			g_object_unref (client);
-
 		e_source_combo_box_set_active (
 			E_SOURCE_COMBO_BOX (priv->source_selector),
 			e_client_get_source (E_CLIENT (old_client)));
@@ -2897,31 +2898,58 @@ source_changed_cb (ESourceComboBox *source_combo_box, EventPage *epage)
 		if (error)
 			g_error_free (error);
 	} else {
-		comp_editor_set_client (editor, client);
-		if (e_client_check_capability (E_CLIENT (client), CAL_STATIC_CAPABILITY_REQ_SEND_OPTIONS) && priv->is_meeting)
+		gchar *backend_addr = NULL;
+		icaltimezone *zone;
+		ECalClient *cal_client = E_CAL_CLIENT (client);
+
+		g_return_if_fail (cal_client != NULL);
+
+		zone = e_meeting_store_get_timezone (priv->meeting_store);
+		e_cal_client_set_default_timezone (cal_client, zone);
+
+		comp_editor_set_client (editor, cal_client);
+		if (e_client_check_capability (client, CAL_STATIC_CAPABILITY_REQ_SEND_OPTIONS) && priv->is_meeting)
 			event_page_show_options (epage);
 		else
 			event_page_hide_options (epage);
 
-		if (client) {
-			gchar *backend_addr = NULL;
-
-			e_client_get_backend_property_sync (E_CLIENT (client), CAL_BACKEND_PROPERTY_CAL_EMAIL_ADDRESS, &backend_addr, NULL, NULL);
+		e_client_get_backend_property_sync (client, CAL_BACKEND_PROPERTY_CAL_EMAIL_ADDRESS, &backend_addr, NULL, NULL);
 
-			if (priv->is_meeting)
-				event_page_select_organizer (epage, backend_addr);
+		if (priv->is_meeting)
+			event_page_select_organizer (epage, backend_addr);
 
-			set_subscriber_info_string (epage, backend_addr);
-			g_free (backend_addr);
-		}
+		set_subscriber_info_string (epage, backend_addr);
+		g_free (backend_addr);
 
 		sensitize_widgets (epage);
 
-		alarm_list_dialog_set_client (priv->alarm_list_dlg_widget, client);
+		alarm_list_dialog_set_client (priv->alarm_list_dlg_widget, cal_client);
 	}
 }
 
 static void
+source_changed_cb (ESourceComboBox *source_combo_box, EventPage *epage)
+{
+	EventPagePrivate *priv = epage->priv;
+	ESource *source;
+
+	if (comp_editor_page_get_updating (COMP_EDITOR_PAGE (epage)))
+		return;
+
+	source = e_source_combo_box_get_active (source_combo_box);
+
+	if (priv->open_cancellable) {
+		g_cancellable_cancel (priv->open_cancellable);
+		g_object_unref (priv->open_cancellable);
+	}
+	priv->open_cancellable = g_cancellable_new ();
+
+	e_client_utils_open_new (source, E_CLIENT_SOURCE_TYPE_EVENTS, FALSE, priv->open_cancellable,
+				 e_client_utils_authenticate_handler, NULL,
+				 epage_client_opened_cb, epage);
+}
+
+static void
 set_subscriber_info_string (EventPage *epage, const gchar *backend_address)
 {
 	CompEditor *editor;
diff --git a/calendar/gui/dialogs/memo-page.c b/calendar/gui/dialogs/memo-page.c
index 3a53421dd5..9c14fccd0a 100644
--- a/calendar/gui/dialogs/memo-page.c
+++ b/calendar/gui/dialogs/memo-page.c
@@ -96,6 +96,8 @@ struct _MemoPagePrivate {
 	gchar *fallback_address;
 
 	ENameSelector *name_selector;
+
+	GCancellable *open_cancellable;
 };
 
 static void set_subscriber_info_string (MemoPage *mpage, const gchar *backend_address);
@@ -188,8 +190,17 @@ memo_page_dispose (GObject *object)
 
 	priv = MEMO_PAGE (object)->priv;
 
+	if (priv->open_cancellable) {
+		g_cancellable_cancel (priv->open_cancellable);
+		g_object_unref (priv->open_cancellable);
+		priv->open_cancellable = NULL;
+	}
+
 	g_strfreev (priv->address_strings);
+	priv->address_strings = NULL;
+
 	g_free (priv->fallback_address);
+	priv->fallback_address = NULL;
 
 	/* Chain up to parent's dispose() method. */
 	G_OBJECT_CLASS (memo_page_parent_class)->dispose (object);
@@ -373,6 +384,7 @@ memo_page_init (MemoPage *mpage)
 {
 	mpage->priv = G_TYPE_INSTANCE_GET_PRIVATE (
 		mpage, TYPE_MEMO_PAGE, MemoPagePrivate);
+	mpage->priv->open_cancellable = NULL;
 }
 
 /* returns whether changed info text */
@@ -884,37 +896,31 @@ categories_clicked_cb (GtkWidget *button,
 }
 
 static void
-source_changed_cb (ESourceComboBox *source_combo_box,
-                   MemoPage *mpage)
+mpage_client_opened_cb (GObject *source_object, GAsyncResult *result, gpointer user_data)
 {
-	MemoPagePrivate *priv = mpage->priv;
+	ESource *source = E_SOURCE (source_object);
+	EClient *client = NULL;
+	MemoPage *mpage = user_data;
+	MemoPagePrivate *priv;
 	CompEditor *editor;
-	CompEditorFlags flags;
-	ESource *source;
-	ECalClient *client;
 	GError *error = NULL;
 
-	if (comp_editor_page_get_updating (COMP_EDITOR_PAGE (mpage)))
-		return;
+	if (!e_client_utils_open_new_finish (source, result, &client, &error)) {
+		if (g_error_matches (error, E_CLIENT_ERROR, E_CLIENT_ERROR_CANCELLED) ||
+		    g_error_matches (error, G_IO_ERROR, G_IO_ERROR_CANCELLED)) {
+			return;
+		}
+	}
 
 	editor = comp_editor_page_get_editor (COMP_EDITOR_PAGE (mpage));
-	flags = comp_editor_get_flags (editor);
-
-	source = e_source_combo_box_get_active (source_combo_box);
-	client = e_cal_client_new (source, E_CAL_CLIENT_SOURCE_TYPE_MEMOS, &error);
-
-	if (client)
-		g_signal_connect (client, "authenticate", G_CALLBACK (e_client_utils_authenticate_handler), NULL);
+	priv = mpage->priv;
 
-	if (!client || !e_client_open_sync (E_CLIENT (client), FALSE, NULL, &error)) {
+	if (error) {
 		GtkWidget *dialog;
 		ECalClient *old_client;
 
 		old_client = comp_editor_get_client (editor);
 
-		if (client)
-			g_object_unref (client);
-
 		e_source_combo_box_set_active (
 			E_SOURCE_COMBO_BOX (priv->source_selector),
 			e_client_get_source (E_CLIENT (old_client)));
@@ -930,12 +936,22 @@ source_changed_cb (ESourceComboBox *source_combo_box,
 		if (error)
 			g_error_free (error);
 	} else {
-		comp_editor_set_client (editor, client);
+		icaltimezone *zone;
+		CompEditorFlags flags;
+		ECalClient *cal_client = E_CAL_CLIENT (client);
+
+		g_return_if_fail (cal_client != NULL);
+
+		flags = comp_editor_get_flags (editor);
+		zone = comp_editor_get_timezone (editor);
+		e_cal_client_set_default_timezone (cal_client, zone);
+
+		comp_editor_set_client (editor, cal_client);
 
 		if (client) {
 			gchar *backend_addr = NULL;
 
-			e_client_get_backend_property_sync (E_CLIENT (client), CAL_BACKEND_PROPERTY_CAL_EMAIL_ADDRESS, &backend_addr, NULL, NULL);
+			e_client_get_backend_property_sync (client, CAL_BACKEND_PROPERTY_CAL_EMAIL_ADDRESS, &backend_addr, NULL, NULL);
 
 			if (flags & COMP_EDITOR_IS_SHARED)
 				memo_page_select_organizer (mpage, backend_addr);
@@ -949,6 +965,29 @@ source_changed_cb (ESourceComboBox *source_combo_box,
 }
 
 static void
+source_changed_cb (ESourceComboBox *source_combo_box,
+                   MemoPage *mpage)
+{
+	MemoPagePrivate *priv = mpage->priv;
+	ESource *source;
+
+	if (comp_editor_page_get_updating (COMP_EDITOR_PAGE (mpage)))
+		return;
+
+	source = e_source_combo_box_get_active (source_combo_box);
+
+	if (priv->open_cancellable) {
+		g_cancellable_cancel (priv->open_cancellable);
+		g_object_unref (priv->open_cancellable);
+	}
+	priv->open_cancellable = g_cancellable_new ();
+
+	e_client_utils_open_new (source, E_CLIENT_SOURCE_TYPE_MEMOS, FALSE, priv->open_cancellable,
+				 e_client_utils_authenticate_handler, NULL,
+				 mpage_client_opened_cb, mpage);
+}
+
+static void
 set_subscriber_info_string (MemoPage *mpage,
                             const gchar *backend_address)
 {
diff --git a/calendar/gui/dialogs/recurrence-page.c b/calendar/gui/dialogs/recurrence-page.c
index c22138f6b9..fa18e0d9f1 100644
--- a/calendar/gui/dialogs/recurrence-page.c
+++ b/calendar/gui/dialogs/recurrence-page.c
@@ -588,22 +588,15 @@ sensitize_recur_widgets (RecurrencePage *rpage)
 }
 
 static void
-sensitize_buttons (RecurrencePage *rpage)
+update_with_readonly (RecurrencePage *rpage, gboolean read_only)
 {
 	RecurrencePagePrivate *priv = rpage->priv;
 	CompEditor *editor;
 	CompEditorFlags flags;
-	gboolean read_only, sensitize = TRUE;
 	gint selected_rows;
-	icalcomponent *icalcomp;
-	ECalClient *client;
-	const gchar *uid;
-
-	if (priv->comp == NULL)
-		return;
+	gboolean sensitize = TRUE;
 
 	editor = comp_editor_page_get_editor (COMP_EDITOR_PAGE (rpage));
-	client = comp_editor_get_client (editor);
 	flags = comp_editor_get_flags (editor);
 
 	if (flags & COMP_EDITOR_MEETING)
@@ -612,39 +605,110 @@ sensitize_buttons (RecurrencePage *rpage)
 	selected_rows = gtk_tree_selection_count_selected_rows (
 		gtk_tree_view_get_selection (GTK_TREE_VIEW (priv->exception_list)));
 
-	read_only = e_client_is_readonly (E_CLIENT (client));
+	if (!read_only)
+		sensitize_recur_widgets (rpage);
+	else
+		gtk_widget_set_sensitive (priv->params, FALSE);
 
-	if (!read_only) {
-		e_cal_component_get_uid (priv->comp, &uid);
+	gtk_widget_set_sensitive (priv->recurs, !read_only && sensitize);
+	gtk_widget_set_sensitive (priv->exception_add, !read_only && e_cal_component_has_recurrences (priv->comp) && sensitize);
+	gtk_widget_set_sensitive (priv->exception_modify, !read_only && selected_rows > 0 && sensitize);
+	gtk_widget_set_sensitive (priv->exception_delete, !read_only && selected_rows > 0 && sensitize);
+}
 
-		if (e_client_check_capability (E_CLIENT (client), CAL_STATIC_CAPABILITY_NO_CONV_TO_RECUR) && e_cal_client_get_object_sync (client, uid, NULL, &icalcomp, NULL, NULL)) {
-			read_only = TRUE;
-			icalcomponent_free (icalcomp);
+static void
+rpage_get_objects_for_uid_cb (GObject *source_object, GAsyncResult *result, gpointer user_data)
+{
+	ECalClient *client = E_CAL_CLIENT (source_object);
+	RecurrencePage *rpage = user_data;
+	GSList *ecalcomps = NULL;
+	GError *error = NULL;
+
+	if (result && !e_cal_client_get_objects_for_uid_finish (client, result, &ecalcomps, &error)) {
+		ecalcomps = NULL;
+		if (g_error_matches (error, E_CLIENT_ERROR, E_CLIENT_ERROR_CANCELLED) ||
+		    g_error_matches (error, G_IO_ERROR, G_IO_ERROR_CANCELLED)) {
+			return;
 		}
+	}
 
-		if (!read_only) {
-			GSList *list = NULL;
+	update_with_readonly (rpage, g_slist_length (ecalcomps) > 1);
 
-			/* see if we have detached instances */
-			if (e_cal_client_get_objects_for_uid_sync (client, uid, &list, NULL, NULL)) {
-				if (list && g_slist_length (list) > 1)
-					read_only = TRUE;
+	g_slist_foreach (ecalcomps, (GFunc) g_object_unref, NULL);
+	g_slist_free (ecalcomps);
+}
 
-				g_slist_foreach (list, (GFunc) g_object_unref, NULL);
-				g_slist_free (list);
-			}
+static void
+rpage_get_object_cb (GObject *source_object, GAsyncResult *result, gpointer user_data)
+{
+	ECalClient *client = E_CAL_CLIENT (source_object);
+	RecurrencePage *rpage = user_data;
+	icalcomponent *icalcomp = NULL;
+	const gchar *uid = NULL;
+	GError *error = NULL;
+
+	if (result && !e_cal_client_get_object_finish (client, result, &icalcomp, &error)) {
+		icalcomp = NULL;
+		if (g_error_matches (error, E_CLIENT_ERROR, E_CLIENT_ERROR_CANCELLED) ||
+		    g_error_matches (error, G_IO_ERROR, G_IO_ERROR_CANCELLED)) {
+			return;
 		}
 	}
 
-	if (!read_only)
-		sensitize_recur_widgets (rpage);
-	else
-		gtk_widget_set_sensitive (priv->params, FALSE);
+	if (icalcomp) {
+		icalcomponent_free (icalcomp);
+		update_with_readonly (rpage, TRUE);
+		return;
+	}
 
-	gtk_widget_set_sensitive (priv->recurs, !read_only && sensitize);
-	gtk_widget_set_sensitive (priv->exception_add, !read_only && e_cal_component_has_recurrences (priv->comp) && sensitize);
-	gtk_widget_set_sensitive (priv->exception_modify, !read_only && selected_rows > 0 && sensitize);
-	gtk_widget_set_sensitive (priv->exception_delete, !read_only && selected_rows > 0 && sensitize);
+	if (rpage->priv->comp)
+		e_cal_component_get_uid (rpage->priv->comp, &uid);
+
+	if (!uid || !*uid) {
+		update_with_readonly (rpage, FALSE);
+		return;
+	}
+
+	/* see if we have detached instances */
+	e_cal_client_get_objects_for_uid (client, uid, rpage->priv->cancellable, rpage_get_objects_for_uid_cb, rpage);
+}
+
+static void
+sensitize_buttons (RecurrencePage *rpage)
+{
+	RecurrencePagePrivate *priv = rpage->priv;
+	CompEditor *editor;
+	ECalClient *client;
+	const gchar *uid;
+
+	if (priv->comp == NULL)
+		return;
+
+	editor = comp_editor_page_get_editor (COMP_EDITOR_PAGE (rpage));
+	client = comp_editor_get_client (editor);
+
+	if (e_client_is_readonly (E_CLIENT (client))) {
+		update_with_readonly (rpage, TRUE);
+		return;
+	}
+
+	if (priv->cancellable) {
+		g_cancellable_cancel (priv->cancellable);
+		g_object_unref (priv->cancellable);
+	}
+	priv->cancellable = g_cancellable_new ();
+
+	e_cal_component_get_uid (priv->comp, &uid);
+	if (!uid || !*uid) {
+		update_with_readonly (rpage, FALSE);
+		return;
+	}
+
+	if (e_client_check_capability (E_CLIENT (client), CAL_STATIC_CAPABILITY_NO_CONV_TO_RECUR)) {
+		e_cal_client_get_object (client, uid, NULL, priv->cancellable, rpage_get_object_cb, rpage);
+	} else {
+		rpage_get_object_cb (G_OBJECT (client), NULL, rpage);
+	}
 }
 
 #if 0
diff --git a/calendar/gui/dialogs/task-page.c b/calendar/gui/dialogs/task-page.c
index c48888008f..958eac682b 100644
--- a/calendar/gui/dialogs/task-page.c
+++ b/calendar/gui/dialogs/task-page.c
@@ -124,6 +124,8 @@ struct _TaskPagePrivate {
 	gboolean is_assignment;
 
 	ESendOptionsDialog *sod;
+
+	GCancellable *open_cancellable;
 };
 
 static const gint classification_map[] = {
@@ -394,6 +396,12 @@ task_page_dispose (GObject *object)
 
 	priv = TASK_PAGE_GET_PRIVATE (object);
 
+	if (priv->open_cancellable) {
+		g_cancellable_cancel (priv->open_cancellable);
+		g_object_unref (priv->open_cancellable);
+		priv->open_cancellable = NULL;
+	}
+
 	if (priv->main != NULL) {
 		g_object_unref (priv->main);
 		priv->main = NULL;
@@ -1006,6 +1014,7 @@ task_page_init (TaskPage *tpage)
 {
 	tpage->priv = TASK_PAGE_GET_PRIVATE (tpage);
 	tpage->priv->deleted_attendees = g_ptr_array_new ();
+	tpage->priv->open_cancellable = NULL;
 }
 
 void
@@ -1695,42 +1704,33 @@ due_date_changed_cb (TaskPage *tpage)
 }
 
 static void
-source_changed_cb (ESourceComboBox *source_combo_box, TaskPage *tpage)
+tpage_client_opened_cb (GObject *source_object, GAsyncResult *result, gpointer user_data)
 {
-	TaskPagePrivate *priv = tpage->priv;
+	ESource *source = E_SOURCE (source_object);
+	EClient *client = NULL;
+	TaskPage *tpage = user_data;
+	TaskPagePrivate *priv;
 	CompEditor *editor;
-	ESource *source;
-	ECalClient *client;
 	GError *error = NULL;
 
-	editor = comp_editor_page_get_editor (COMP_EDITOR_PAGE (tpage));
-	source = e_source_combo_box_get_active (source_combo_box);
-
-	if (comp_editor_page_get_updating (COMP_EDITOR_PAGE (tpage)))
-		return;
-
-	client = e_cal_client_new (source, E_CAL_CLIENT_SOURCE_TYPE_TASKS, &error);
-	if (client) {
-		icaltimezone *zone;
-
-		zone = comp_editor_get_timezone (editor);
-		e_cal_client_set_default_timezone (client, zone);
+	if (!e_client_utils_open_new_finish (source, result, &client, &error)) {
+		if (g_error_matches (error, E_CLIENT_ERROR, E_CLIENT_ERROR_CANCELLED) ||
+		    g_error_matches (error, G_IO_ERROR, G_IO_ERROR_CANCELLED)) {
+			return;
+		}
 	}
 
-	if (client)
-		g_signal_connect (client, "authenticate", G_CALLBACK (e_client_utils_authenticate_handler), NULL);
-
-	if (!client || !e_client_open_sync (E_CLIENT (client), FALSE, NULL, &error)) {
+	editor = comp_editor_page_get_editor (COMP_EDITOR_PAGE (tpage));
+	priv = tpage->priv;
+	if (error) {
 		GtkWidget *dialog;
+		ECalClient *old_client;
 
-		if (client)
-			g_object_unref (client);
-
-		client = comp_editor_get_client (editor);
+		old_client = comp_editor_get_client (editor);
 
 		e_source_combo_box_set_active (
 			E_SOURCE_COMBO_BOX (priv->source_selector),
-			e_client_get_source (E_CLIENT (client)));
+			e_client_get_source (E_CLIENT (old_client)));
 
 		dialog = gtk_message_dialog_new (NULL, GTK_DIALOG_MODAL,
 						 GTK_MESSAGE_WARNING, GTK_BUTTONS_OK,
@@ -1743,9 +1743,17 @@ source_changed_cb (ESourceComboBox *source_combo_box, TaskPage *tpage)
 		if (error)
 			g_error_free (error);
 	} else {
-		comp_editor_set_client (editor, client);
+		icaltimezone *zone;
+		ECalClient *cal_client = E_CAL_CLIENT (client);
+
+		g_return_if_fail (cal_client != NULL);
+
+		zone = comp_editor_get_timezone (editor);
+		e_cal_client_set_default_timezone (cal_client, zone);
+
+		comp_editor_set_client (editor, cal_client);
 		comp_editor_page_changed (COMP_EDITOR_PAGE (tpage));
-		if (e_client_check_capability (E_CLIENT (client), CAL_STATIC_CAPABILITY_REQ_SEND_OPTIONS) && priv->is_assignment)
+		if (e_client_check_capability (client, CAL_STATIC_CAPABILITY_REQ_SEND_OPTIONS) && priv->is_assignment)
 			task_page_show_options (tpage);
 		else
 			task_page_hide_options (tpage);
@@ -1753,7 +1761,7 @@ source_changed_cb (ESourceComboBox *source_combo_box, TaskPage *tpage)
 		if (client) {
 			gchar *backend_addr = NULL;
 
-			e_client_get_backend_property_sync (E_CLIENT (client), CAL_BACKEND_PROPERTY_CAL_EMAIL_ADDRESS, &backend_addr, NULL, NULL);
+			e_client_get_backend_property_sync (client, CAL_BACKEND_PROPERTY_CAL_EMAIL_ADDRESS, &backend_addr, NULL, NULL);
 
 			if (priv->is_assignment)
 				task_page_select_organizer (tpage, backend_addr);
@@ -1767,6 +1775,28 @@ source_changed_cb (ESourceComboBox *source_combo_box, TaskPage *tpage)
 }
 
 static void
+source_changed_cb (ESourceComboBox *source_combo_box, TaskPage *tpage)
+{
+	TaskPagePrivate *priv = tpage->priv;
+	ESource *source;
+
+	if (comp_editor_page_get_updating (COMP_EDITOR_PAGE (tpage)))
+		return;
+
+	source = e_source_combo_box_get_active (source_combo_box);
+
+	if (priv->open_cancellable) {
+		g_cancellable_cancel (priv->open_cancellable);
+		g_object_unref (priv->open_cancellable);
+	}
+	priv->open_cancellable = g_cancellable_new ();
+
+	e_client_utils_open_new (source, E_CLIENT_SOURCE_TYPE_TASKS, FALSE, priv->open_cancellable,
+				 e_client_utils_authenticate_handler, NULL,
+				 tpage_client_opened_cb, tpage);
+}
+
+static void
 set_subscriber_info_string (TaskPage *tpage, const gchar *backend_address)
 {
 	CompEditor *editor;
diff --git a/plugins/mail-to-task/mail-to-task.c b/plugins/mail-to-task/mail-to-task.c
index ddcd1328d1..a39456a00f 100644
--- a/plugins/mail-to-task/mail-to-task.c
+++ b/plugins/mail-to-task/mail-to-task.c
@@ -827,6 +827,20 @@ do_mail_to_event (AsyncData *data)
 		struct icaltimetype tt, tt2;
 		struct _manage_comp *oldmc = NULL;
 
+		#define cache_backend_prop(prop) {							\
+			gchar *val = NULL;								\
+			e_client_get_backend_property_sync (E_CLIENT (client), prop, &val, NULL, NULL);	\
+			g_free (val);									\
+		}
+
+		/* precache backend properties, thus editor have them ready when needed */
+		cache_backend_prop (CAL_BACKEND_PROPERTY_CAL_EMAIL_ADDRESS);
+		cache_backend_prop (CAL_BACKEND_PROPERTY_ALARM_EMAIL_ADDRESS);
+		cache_backend_prop (CAL_BACKEND_PROPERTY_DEFAULT_OBJECT);
+		e_client_get_capabilities (E_CLIENT (client));
+
+		#undef cache_backend_prop
+
 		/* set start day of the event as today, without time - easier than looking for a calendar's time zone */
 		tt = icaltime_today ();
 		dt.value = &tt;