Thank you for the replys,
I went with zentara suggestion. and changed the code to the following:

$Search_Listbox = $mw->Scrolled("Listbox",
    -background => "white",
    -scrollbars => "osoe",
    -height => 7,
    -width => 47,
    -listvariable => \@Test);
$Search_Listbox->place(-x => 5, -y => 150);
[download]

which solved all my problems.
*** Case Closed ***