#!/usr/bin/perl

# https://perlmonks.org/?node_id=1223174

use strict;
use warnings;
use Tk;

#use CoolFrame;
{
package Tk::CoolFrame;

use strict;
use warnings;

use vars qw/$VERSION/;
$VERSION = '1.0';

use base qw(Tk::Frame);
Construct Tk::Widget 'CoolFrame';

sub ClassInit {
    my($class, $mw) = @_;
    $class->SUPER::ClassInit($mw);
}

sub Populate {
    my($self, $args) = @_;
    $self->SUPER::Populate($args);

    my $outer = $self->Frame()->pack(-fill=> 'both', -expand=> 1);
    my $inner = $outer->Frame()->pack(-fill=> 'both', -expand=> 1);

    $self->ConfigSpecs( 
        -background  => [{-background => $inner}, 'background', 'Background', '#d9d9d9'],    # grey
        -bordercolor => [{-background => $outer}, 'bordercolor', 'Bordercolor', '#000000'],  # black
        -borderwidth => [{-borderwidth => $outer}, 'borderwidth', 'Borderwidth', 1],
        'DEFAULT'    => [$outer],
    );

    $self->{outer} = $outer;
    $self->{inner} = $inner;

    $self->Delegates('Construct' => $inner); # <--- add this


}
}

################################################### package main;

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

my $frame = $mw->CoolFrame(
    -bordercolor => 'red',
    -background=> 'white',
)->pack(-padx => 5, -pady => 5);

# # THIS WORKS
# my $button = $frame->{'inner'}->Button(
#     -text=> "Exit",
#     -command=> sub{ exit; },
# )->pack(-padx => 5, -pady => 5);

# THIS IS WHAT I WOULD LIKE TO DO!
my $button = $frame->Button(
    -text=> "Exit",
    -command=> sub{ exit; },
)->pack(-padx => 5, -pady => 5);

MainLoop();