#!/usr/bin/perl
use Tk;

$mw = tkinit;
$t = $mw->Toplevel;
$t->withdraw;
$t->Label(-text => "Testing...")->pack;
$t->Button(
   -text => "Withdraw",
   -command => sub {$t->withdraw},
)->pack;
$t ->overrideredirect(1); #to top on all virtual desktops 

$mw->Button(
   -text => 'Test',
   -command => sub {
       $_->deiconify, $_->raise for $t;
   },
)->pack;

MainLoop;