Tree and HList both support that feature. Look at the documentation for hide and show methods in the documentation for HList, and for the -state => 'normal'. The trick however is that you must call setmode on each node in the tree to set its initial state.

use strict;
use warnings;
use Tk;
use Tk::Tree;

my $main = MainWindow->new(-title => "Demo" );
my $tree = $main->ScrlTree(
    -font       => 'FixedSys 8',
    -itemtype   => 'text',
    -separator  => '/',
    -scrollbars => "se",
    -selectmode => 'single',
);

$tree->pack( -fill => 'both', -expand => 1 );

$tree->add ('root', -text => 'root of all ...', -state => 'normal' );
$tree->add ('root/top 1', -text => 'first top level node', -state => '
+normal' );
$tree->add ('root/top 2', -text => 'second top level node', -state => 
+'normal' );
$tree->add ('root/top 2/nested 1', -text => 'first nested node', -stat
+e => 'normal' );
$tree->add ('root/top 2/nested 2', -text => 'second nested node', -sta
+te => 'normal' );

openTree ($tree);

MainLoop;

sub openTree {
    my $tree = shift;
    my ( $entryPath, $openChildren ) = @_;
    my @children = $tree->info( children => $entryPath );

    return if !@children;

    for (@children) {
        openTree( $tree, $_, 1 );
        $tree->show( 'entry' => $_ ) if $openChildren;
    }
    $tree->setmode( $entryPath, 'close' ) if length $entryPath;
}

sub closeTree {
    my $tree = shift;
    my ( $entryPath, $hideChildren ) = @_;
    my @children = $tree->info( children => $entryPath );

    return if !@children;

    for (@children) {
        closeTree( $tree, $_, 1 );
        $tree->hide( 'entry' => $_ ) if $hideChildren;
    }
    $tree->setmode( $entryPath, 'open' ) if length $entryPath;
}
[download]

thanks a lot!

Happy to help. It was a while ago that I first used Tk::Tree, but I seem to remember it took some time to figure out what the trick was!

---

Perl reduces RSI - it saves typing

#! /usr/bin/perl -w
use strict;
use Gtk2 '-init';
use Glib qw/TRUE FALSE/; 
 
#standard window creation, placement, and signal connecting
my $window = Gtk2::Window->new('toplevel');
$window->signal_connect('delete_event' => sub { Gtk2->main_quit; });
$window->set_border_width(5);
$window->set_position('center_always');

#this vbox will geturn the bulk of the gui
my $vbox = &ret_vbox();

#add and show the vbox
$window->add($vbox);
$window->show();

#our main event-loop
Gtk2->main();


sub ret_vbox {

my $vbox = Gtk2::VBox->new(FALSE,5);

    #create a scrolled window that will host the treeview
    my $sw = Gtk2::ScrolledWindow->new (undef, undef);
            $sw->set_shadow_type ('etched-out');
        $sw->set_policy ('automatic', 'automatic');
        #This is a method of the Gtk2::Widget class,it will force a mi
+nimum 
        #size on the widget. Handy to give intitial size to a 
        #Gtk2::ScrolledWindow class object
        $sw->set_size_request (300, 300);
        #method of Gtk2::Container
        $sw->set_border_width(5);
    
    #this is one of the provided base Gtk2::TreeModel classes.
    my $tree_store = Gtk2::TreeStore->new(qw/Glib::String/);

    #fill it with arbitry data
    foreach my $parent_nr (1..30) {
        #the iter is a pointer in the treestore. We
        #use to add data.
                my $iter = $tree_store->append(undef);
        $tree_store->set ($iter,0 => "Parent $parent_nr");
        
                 foreach my $child (1..3){
             #here we append child iters to the parent iter
            #and add data to those chils iters.
                      my $iter_child = $tree_store->append($iter);
              $tree_store->set ($iter_child,0 => "Child $child of Pare
+nt $parent_nr");
                 
        
                  foreach my $gchild (1..3){
                    #here we append child iters to the parent iter
                   #and add data to those chils iters.
                                my $iter_child = $tree_store->append($
+iter_child);
                            $tree_store->set ($iter_child,0 => "GrandC
+hild $gchild of Parent $parent_nr");
                  }
        }
    }
    
    #this will create a treeview, specify $tree_store as its model
    my $tree_view = Gtk2::TreeView->new($tree_store);

        
        #create a Gtk2::TreeViewColumn to add to $tree_view
        my $tree_column = Gtk2::TreeViewColumn->new();
        
        $tree_column->set_title ("Click to sort");
            
            #create a renderer that will be used to display info
            #in the model
            my $renderer = Gtk2::CellRendererText->new;
        #add this renderer to $tree_column. This works like a Gtk2::Hb
+ox
        # so you can add more than one renderer to $tree_column       
+     
        $tree_column->pack_start ($renderer, FALSE);
        
         # set the cell "text" attribute to column 0   
         #- retrieve text from that column in treestore 
         # Thus, the "text" attribute's value will depend on the row's
+ value
         # of column 0 in the model($treestore),
         # and this will be displayed by $renderer,
         # which is a text renderer
        $tree_column->add_attribute($renderer, text => 0);
    
    #add $tree_column to the treeview
    $tree_view->append_column ($tree_column);
    
     # make it searchable
       $tree_view->set_search_column(0);
    
        # Allow sorting on the column
        $tree_column->set_sort_column_id(0);
   
    # Allow drag and drop reordering of rows
        $tree_view->set_reorderable(TRUE);
    
    $sw->add($tree_view);
    
$vbox->pack_start($sw,TRUE,TRUE,0);
$vbox->show_all();
return $vbox;
}
[download]

Also, BWidget has another tree widget

Also, BLT has another tree widget