#Stephen Lidie wrote:
#There are at least two ways of doing it: ferreting out the actual  
#superclass callback and invoking it manually (not recommended), or  
#creating a proper mega-widget.  The mega-widget method is cleaner and  
#seems to do what you want.

#Here is a modified version of the Emu example.  First, note that I  
#added Tk::Derived to the module's base class because we need to turn  
#this into a first class mega-widget - it's no longer a simple example.  
#Second, the <Enter> binding has been deleted from the class  
#initialization method ClassInit().

-------------------------------------------------------------
use Tk;
use strict;

package MyButton;

use base qw/Tk::Derived Tk::Button/;
Construct Tk::Widget 'MyButton';

sub ClassInit {
     my ($class, $mw) = @_;
     $class->SUPER::ClassInit($mw);
#    $mw->bind($class, '<Enter>', sub{print "Entered a MyButton\n"});
}

sub Populate {
     my ($self, $args) = @_;
     $self->SUPER::Populate($args);
     $self->bind('<Enter>', sub{print "Entered a MyButton\n"});
#    my (@bt) = $self->bindtags;
#    $self->bindtags( [ @bt[ 1, 0, 2, 3 ] ] );
}

1;

package main;

my $mw = MainWindow->new;
$mw->Button(-text => 'NormalButton')->pack;
$mw->MyButton(-text => 'MyButton')->pack;

MainLoop;
#--------------------------------------------------------------

#The real change is the addition of Populate(), the class instance  
#constructor. It's responsible for creating the <Enter> binding.  Now  
#when you <Enter> a MyButton mega-widget it behaves exactly as a normal  
#Button does, plus, it prints a message.