[balsa/gtk4: 112/311] main-window: Stop using GtkButtonBox

[Peter Bloomfield <peterb src gnome org>]

commit 693af90b5375fc08e75c70963a80cece749680c7
Author: Peter Bloomfield <PeterBloomfield bellsouth net>
Date:   Sat Aug 29 19:41:24 2020 -0400

    main-window: Stop using GtkButtonBox

 src/main-window.c | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)
---
diff --git a/src/main-window.c b/src/main-window.c
index c341f973f..59aac0692 100644
--- a/src/main-window.c
+++ b/src/main-window.c
@@ -3906,18 +3906,16 @@ bw_find_real(BalsaWindow * window, BalsaIndex * bindex, gboolean again)
        gtk_container_add(GTK_CONTAINER(vbox), frame);
 
        /* Button box */
-       box = gtk_button_box_new(GTK_ORIENTATION_HORIZONTAL);
+       box = gtk_box_new(GTK_ORIENTATION_HORIZONTAL, 0);
        gtk_container_set_border_width(GTK_CONTAINER(box), 6);
-       button = gtk_button_new_with_mnemonic(_("_Apply"));
+        button = libbalsa_add_button_to_box(_("_Apply"), box, GTK_ALIGN_START);
        g_signal_connect(button, "clicked",
                         G_CALLBACK(bw_find_button_clicked),
                         GINT_TO_POINTER(FIND_RESPONSE_FILTER));
-       gtk_container_add(GTK_CONTAINER(box), button);
-       button = gtk_button_new_with_mnemonic(_("_Clear"));
+        button = libbalsa_add_button_to_box(_("_Clear"), box, GTK_ALIGN_END);
        g_signal_connect(button, "clicked",
                         G_CALLBACK(bw_find_button_clicked),
                         GINT_TO_POINTER(FIND_RESPONSE_RESET));
-       gtk_container_add(GTK_CONTAINER(box), button);
        gtk_container_add(GTK_CONTAINER(frame), box);
 
        /* Frame with OK button */