After a lot of tries, I discover a solution which seems to be the good one : the
"-style" option must include the constant WS_VISIBLE.
My code works well as this :
$mainWin->AddListbox(
-name => "listBox",
-left => 500,
-top => 200,
-width => 150,
-height => 80,
-style => WS_VISIBLE | WS_VSCROLL,
);
Thanks to all for your answers and have a good Perl programming day.
Patrick.
