use strict;
use Tk;


my $lst_properties;
my $chk_options;
my $chkoptions;
my $MainWindow;

&maingui;

sub maingui {


    $MainWindow = MainWindow->new(-title=>'Listbox');
    $chk_options = $MainWindow -> Checkbutton ( -anchor=>'nw',
			-justify=>'left',-relief=>'flat',
			-indicatoron=>1,-text=>'Additional Criteria',
			-variable=>\$chkoptions, -state=>'normal',
			-command=>\&Additional_Criteria
			) -> grid(-row=>1,-column=>0,-pady=>5);
    $lst_properties= $MainWindow -> Scrolled ( 'Listbox',
			-selectmode=>'single', -relief=>'sunken',
			-scrollbars=>'osoe',-width=>50,-state=>'disabled');
    $lst_properties -> insert('end',"People","Animals","Aliens","Meat",
			"Fruit","Vegies","Dairy","Pultry",
			);
    $lst_properties -> grid(-row=>5,-column=>1,-pady=>3);
   
 MainLoop;
}

sub Additional_Criteria
{
 #code her to test if check box is selected or not

   if ($chkoptions) {
      print "Enable\n";
      #Code here to ENABLE ListBox
   }
   else {
      print "Disable\n";
      #Code here to DISABLE ListBox
   }
}