[balsa/wip/gtk4] balsa-mime-widget-callbacks: Use GtkWidget API

[Peter Bloomfield <peterb src gnome org>]

commit 1b1e30059d0949794a27b8c8831117adc64fe6c6
Author: Peter Bloomfield <PeterBloomfield bellsouth net>
Date:   Thu Aug 2 16:59:23 2018 -0400

    balsa-mime-widget-callbacks: Use GtkWidget API
    
    to replace the use of gtk_container_set_focus_chain(); specifically,
    unset can-focus on all widgets, then set can-focus on the current
    widget.

 src/balsa-mime-widget-callbacks.c | 28 ++++++++++++++--------------
 1 file changed, 14 insertions(+), 14 deletions(-)
---
diff --git a/src/balsa-mime-widget-callbacks.c b/src/balsa-mime-widget-callbacks.c
index 991e3ee72..a8f5ae150 100644
--- a/src/balsa-mime-widget-callbacks.c
+++ b/src/balsa-mime-widget-callbacks.c
@@ -261,34 +261,34 @@ balsa_mime_widget_key_press_event(GtkEventControllerKey *key_controller,
 }
 
 
+static void
+bmw_set_can_focus(GtkWidget *widget,
+                  gpointer   data)
+{
+    if (GTK_IS_CONTAINER(widget))
+        gtk_container_foreach(GTK_CONTAINER(widget), bmw_set_can_focus, data);
+    gtk_widget_set_can_focus(widget, GPOINTER_TO_INT(data));
+}
+
 void
 balsa_mime_widget_check_focus(GtkWidget * widget, GParamSpec * pspec, BalsaMessage * bm)
 {
-#if 0
-    GtkContainer *container =
-        GTK_CONTAINER(balsa_mime_widget_get_container(balsa_message_get_bm_widget(bm)));
-#endif
+    GtkWidget *container =
+        balsa_mime_widget_get_container(balsa_message_get_bm_widget(bm));
     BalsaMessageFocusState focus_state;
 
     focus_state = balsa_message_get_focus_state(bm);
 
     if (gtk_widget_has_focus(widget)) {
-#if 0
         /* Disable can_focus on other message parts so that TAB does not
          * attempt to move the focus on them. */
-        GList *list;
-
-        list = g_list_append(NULL, widget);
-        gtk_container_set_focus_chain(container, list);
-        g_list_free(list);
-#endif
+        bmw_set_can_focus(container, GINT_TO_POINTER(FALSE));
+        gtk_widget_set_can_focus(widget, TRUE);
 
         if (focus_state == BALSA_MESSAGE_FOCUS_STATE_NO)
             balsa_message_set_focus_state(bm, BALSA_MESSAGE_FOCUS_STATE_YES);
     } else {
-#if 0
-        gtk_container_unset_focus_chain(container);
-#endif
+        bmw_set_can_focus(container, GINT_TO_POINTER(TRUE));
 
         if (balsa_message_get_message(bm) != NULL) {
             if (focus_state == BALSA_MESSAGE_FOCUS_STATE_HOLD) {