Hi, this sounds like the type of question only Slaven Rezic can answer :-). From your description, I think "eventGenerate" may be of use to you.

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

my $mw = new Tk::MainWindow;

my $btn = $mw->Button(-text => 'Hit Return',
           -command=> sub{
        print 'Used Button'
       }
            )->pack();

my $btn_eg = $mw->Button(-text => 'Generate Return',
             -command=> sub{
         $mw->eventGenerate('<Return>');
       }
            )->pack();
#
# Note that we *usually* bind to the main window,
#  not the button - it's a focus thing.
#
$mw->bind('<Return>', \&_on_rtn);


MainLoop;
exit(0);

sub _on_rtn
    {
    $mw->messageBox(
     -message=>'Thanx for using the keyboard!');
    }
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