Maybe someone knows a better answer, but my understanding is that the Frame is a no frill container widget, and dosn't have the builtin internal bindings to respond to keys. Focus is the important concept, read "perldoc Tk::focus". Usually one binds to the $mw (toplevel) and sets the focus order of the widgets it holds.

This first script shows the simplicity of the frame, notice no @_ is passed thru

#!/usr/bin/perl
use Tk;

my $main = new MainWindow;
my $f = $main->Frame(-width => 100, -height => 100)->pack;

$f->bind('<Key>'   => sub {print "Key: @_\n"} );
$f->bind('<Enter>' => sub { print "enter @_\n" } );
$f->bind('<Leave>' => sub { print "leave @_\n" } );

$f->focus;
MainLoop;
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and here is a way around the problem

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

my $mw = MainWindow->new;

my $f = $mw->Frame(-width => 100, -height => 100)->pack;

#$mw->bind( '<KeyPress>' => \&print_keysym );
$f->bind( '<KeyPress>' => \&print_keysym );

$mw->Button(
    -text    => 'Exit',
    -command => sub { exit(); }
)->pack;

#button gets the default window focus, so we need
# to give it to the frame

$f->focus; # won't work without this

MainLoop;

sub print_keysym {
    my $widget = shift;
    my $e      = $widget->XEvent;
    my ( $keysym_text, $keysym_decimal ) = ( $e->K, $e->N );
    print "keysym=$keysym_text, numberic=$keysym_decimal\n";
}
[download]