You can do this real easy with the Tk overrideredirect and geometry methods. Here is a simple example. In a real case, you might want to add a menu" with a right-click, etc.etc.

#!/usr/bin/perl
use warnings;
use strict;
use Tk;
use Tk::ProgressBar;

my $mw = MainWindow->new();
$mw->overrideredirect(1);
$mw->geometry('-0-0');

my $p = $mw->ProgressBar(
    -blocks   => 1,
    -width    => 20,
    -length   => 200,
    -from     => 0,
    -to       => 100,
    -variable => \( my $foo ),
    -colors => [0,'hotpink'],
)->pack();

$foo = 0;
$mw->repeat( 10, sub { $foo = ( $foo + 1 ) % 100 } );

MainLoop;
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