[balsa/gtk4] message-window: Connect to "close-request" signal

[Peter Bloomfield <peterb src gnome org>]

commit 7addd4a7689b8f735e4662afe3b6f926c56a705c
Author: Peter Bloomfield <PeterBloomfield bellsouth net>
Date:   Thu Nov 19 17:27:56 2020 -0500

    message-window: Connect to "close-request" signal
    
    GtkWindow does not emit the "destroy" signal when it is being destroyed.

 src/message-window.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)
---
diff --git a/src/message-window.c b/src/message-window.c
index f8096e7c1..2213ac583 100644
--- a/src/message-window.c
+++ b/src/message-window.c
@@ -352,9 +352,9 @@ mw_set_message(MessageWindow * mw, LibBalsaMessage * message)
     }
 }
 
-/* Handler for the "destroy" signal for mw->window. */
-static void
-destroy_message_window(GtkWidget * widget, MessageWindow * mw)
+/* Handler for the "close-request" signal for mw->window. */
+static gboolean
+mw_close_request(GtkWidget * widget, MessageWindow * mw)
 {
     if (mw->bindex) {           /* BalsaIndex still exists */
         g_object_weak_unref(G_OBJECT(mw->bindex), mw_bindex_closed_cb, mw);
@@ -380,6 +380,8 @@ destroy_message_window(GtkWidget * widget, MessageWindow * mw)
     mw_set_message(mw, NULL);
 
     g_free(mw);
+
+    return FALSE;
 }
 
 /* Handler for the mailbox's "message-expunged" signal */
@@ -900,8 +902,7 @@ message_window_new(LibBalsaMailbox * mailbox, guint msgno)
     mw->toolbar = balsa_toolbar_new(model, G_ACTION_MAP(window));
     gtk_box_append(GTK_BOX(vbox), mw->toolbar);
 
-    g_signal_connect(window, "destroy",
-                    G_CALLBACK(destroy_message_window), mw);
+    g_signal_connect(window, "close-request", G_CALLBACK(mw_close_request), mw);
 
     mw->bindex = balsa_find_index_by_mailbox(mailbox);
     g_object_weak_ref(G_OBJECT(mw->bindex), mw_bindex_closed_cb, mw);