my $frm1 = $mw -> Frame(-bg=>'LightSkyBlue1') -> pack(-fill => 'x');
my $frm11 = $frm1 -> Frame(-bg=>'LightSkyBlue1') -> pack(-fill => 'x');

my $lst = $frm11 -> Scrolled('Listbox',
                              -width => 50,
                              -height => 5, 
                              -scrollbars => 'oe', 
                              -selectmode => 'single') -> pack();

(generate @lst_files)

$lst -> delete ('0.0', 'end');
$lst -> insert('end', @lst_files);
$mw->update;