diff -up evolution-3.22.6/calendar/gui/e-comp-editor.c.comp-editor-changed evolution-3.22.6/calendar/gui/e-comp-editor.c

--- evolution-3.22.6/calendar/gui/e-comp-editor.c.comp-editor-changed	2016-09-19 10:22:58.000000000 +0200

+++ evolution-3.22.6/calendar/gui/e-comp-editor.c	2017-04-27 17:09:51.444757546 +0200

@@ -1021,12 +1021,16 @@ open_target_client_data_free (gpointer p

 	if (otc) {

 		if (otc->comp_editor) {

 			if (otc->client) {

+				gboolean previous_changed = e_comp_editor_get_changed (otc->comp_editor);

+

 				e_comp_editor_set_alarm_email_address (otc->comp_editor, otc->alarm_email_address);

 				e_comp_editor_set_cal_email_address (otc->comp_editor, otc->cal_email_address);

 				e_comp_editor_set_target_client (otc->comp_editor, E_CAL_CLIENT (otc->client));

 				if (otc->is_target_client_change)

 					e_comp_editor_set_changed (otc->comp_editor, TRUE);

+				else

+					e_comp_editor_set_changed (otc->comp_editor, previous_changed);

 			}

 			if (otc->comp_editor->priv->activity_bar && otc->activity) {