Gtk3::Dialog::new and Gtk3::MessageDialog::new do not handle flags argument properly
In the Perl reimplementation of Gtk3::Dialog::new and Gtk3::MessageDialog::new, the $flags argument is handled like a normal scalar in:
if ($flags & 'modal') {
$dialog->set_modal (Glib::TRUE);
}
if ($flags & 'destroy-with-parent') {
$dialog->set_destroy_with_parent (Glib::TRUE);
}
so the tests are always true (as $flags is an arrayref), so the dialogs are always set to modal and destroy-with-parent.