#!/usr/bin/winperl
use warnings;
use strict;

use Tk;
use Tk::Tree;

my $mw = MainWindow->new();
my $tr = $mw->Tree(
  -command    => sub { print "Tree::command\n" },
)->pack();

$tr->add($_, -text => $_) for qw(Foo Bar Quux);
$tr->addchild('Foo', -text => 'Zod');

$tr->autosetmode();

# Replace normal double-click handler with our special routine
{
  my $old = $mw->bind('Tk::Tree', '<Double-ButtonPress-1>');
  $mw->bind('Tk::Tree', '<Double-ButtonPress-1>', [
    \&invoke,
    Ev('x'),
    Ev('y'),
    $old,
  ]);
}

MainLoop;

sub invoke {
  my ($tree, $x, $y, $old) = @_;

  # Get info about what item was clicked on
  my ($entry, $subitem) = $tree->info('item', $x, $y);

  if(defined($subitem) and $subitem eq 'indicator') {

    #return;  # ignore, if you want

    # Indicator, so just open/close the entry
    $tree->IndicatorCmd($entry, '<Activate>');

  } else {

    # Not indicator, so propagate
    #$tree->Double1();  # Don't do this
    $old->Call($tree);  # Instead, use old callback

  }
}