Hi, read the help files here at perlmonks on posting and wrapping your code in code tags, so its easier for us to read. Anyways, here is the best way to do what you want. You had some errors, and remember, always use warnings and use strict. In your case, I use the -listvariable option of the Listbox widget, to automatically change the array shown.

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

my @cm_tools = ( "CVS", "VSS", "PVCS", "RCS", "Start Team" );

my $mw =  MainWindow->new(); 
$mw->title("ZenSOFT Configuration Tool"); 
$mw->Label(-text => "Top", -background => "red")->pack(); 
$mw->Label(-text=>"CM Tool")-> pack(-expand => '1'); 

my @fruits0 = ('Apple','Banana','Cherry','Date','Elderberry','Fig');
my @fruits1 = ('Apple','Banana');
my @fruits = @fruits1;
my $cm_tool = 'CVS';

$mw->Optionmenu(
        -options=> \@cm_tools,
        -textvariable=>\$cm_tool,
        -width=>'25',
        -command => sub{
           #print "$cm_tool\n";
           if( $cm_tool eq 'VSS'){ @fruits = @fruits0 } 
            else{ @fruits = @fruits1   }
         },
        )->pack(-expand => '1'); 

 
my $fruit_list = $mw->Listbox(
      -listvariable => \@fruits,
       )->pack();; 

my $EndFrame= $mw ->Frame(-width => '40')->pack(-side => "bottom"); 

my $OkButton = $EndFrame->Button(-text => "Next", -width=>'10', 
     -command => sub{$mw->destroy()})->pack(-padx=>'10',-pady=>'5', -s
+ide=>'left'); 

my $CancelButton = $EndFrame->Button(-text => "Cancel", -width=>'10', 
     -command => sub {exit })->pack(-padx=>'10',-pady=>'5', -side=>'ri
+ght'); 

MainLoop();
[download]