Yeah, it's a tricky problem where the $mw has focus, and you need to set it up so the canvas has focus. Uncomment the various lines below, and play with it to see what is happening.

#!/usr/bin/perl -w

use strict;
use Tk;

my $mw = 'MainWindow'->new();

my $cv = $mw->Canvas()->pack();

$mw->bind('<Any-Enter>' => sub { $cv->Tk::focus });
#$cv->Tk::focus;

$cv->Tk::bind( '<KeyPress-a>', sub { print "Ounch!\n" } ); 

#$mw->bind( '<KeyPress-a>', sub { print "Ounch!\n" } ); 

MainLoop();
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