The actual Dialog is shown using the Popup method. Any other options supplied to Show are passed to Popup, and can be used to  position the Dialog on the screen. Please read Tk::Popup for  details.

##</code><code>##

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

my $mw = MainWindow->new();
$mw->geometry("600x400+100+100");

my $dialog = $mw->DialogBox(
         -title => 'Test',
      -buttons => [qw/Yes No Cancel/], 
      );

my $lifter;

$mw->Button(-text=>'Get_dialog',
            -command => sub{
     	    $lifter = $mw->repeat(100,sub{ $dialog->raise });

	    #my $answer = $dialog->Show;
            my $answer = $dialog->Show(-popover => $mw);

	    $lifter->cancel;
	    #do your $dialog return testing 

	    }

  )->pack;
MainLoop;