#!/usr/bin/perl
use warnings;
use strict;
use Tk;
use Tk::HList;
# googled example by Rob Seegel

my $mw = new MainWindow;
my $hl = $mw->Scrolled(
    'HList',
    -scrollbars => 'os',
    -background => 'white',
    -columns    => 4,
    -header     => 1,
    -width      => 40,
    -height     => 5
)->pack;

my $bgcolor = "bisque";

foreach my $column ( 0 .. 3 ) {

## Create the Clickable Header 
    my $b = $hl->Button(
        -background => $bgcolor,
        -anchor     => 'center',
        -text       => "Header$column",
        -command    => sub {
            print "You pressed Header $column\n";
        }
    );

    $hl->headerCreate(
        $column,
        -itemtype         => 'window',
        -borderwidth      => -2,
        -headerbackground => $bgcolor,
        -widget           => $b
    );

}

MainLoop;

##</code><code>##

#!/usr/bin/perl -w
use strict;
use Tk;

#this leaks 

my $mw = Tk::MainWindow->new( -title => 'Listbox Leak' );

my $lb = $mw->Listbox()->pack();
my $b  = $mw->Button(
    -text    => 'Leak',
    -command => \&leak
)->pack();

MainLoop;

sub leak {
    $lb->delete( 0, 'end' );
    $lb->insert( 'end', 1 .. 10000 );
}


##</code><code>##

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

#no leaks, but watch out for @array being empty...crash 
#make sure @array has at least a ''; 
my $mw = Tk::MainWindow->new(-title => 'Listbox Leak');

my @array = (1..10000);

my $lb = $mw->Listbox(
         -listvariable=> \@array,
        )->pack();

my $b = $mw->Button(-text => 'Leak',
        -command => \&leak
          )->pack();

MainLoop;

sub leak {
  @array = map{"$_.a"}(1..10000);
  $lb->update;
}