G'day IB2017,

Referring to the title of your post, the following code dynamically creates menu items.

#!/usr/bin/env perl

use strict;
use warnings;

use Tk;

my $mw = MainWindow::->new();

my $mb = $mw->Menubutton(-text => 'Popup');
my $menu = $mb->menu();
$mb->configure(-menu => $menu);
$mb->pack();

$mw->Button(
    -text => 'Add menu item',
    -command => sub {
        $mb->command(-label => 'A', -command => sub { 1 })
    },
)->pack();

MainLoop;
[download]

This code is fully functional. If you run it and click "Popup", you'll see a menu with no items. Now click "Add menu item" then "Popup" again: you'll see the menu now has one item. You can repeat this process and see the number of menu items growing. You can tearoff the menu and watch it grow dynamically every time you click "Add menu item".

As already pointed out, we can't run the code you posted. It is incomplete and it is not possible to tell you how modify it to do what you ask. Here's a few suggestions:

• $MESS_0 to $MESS_5 does not look good. Consider an array (@MESS) and code $MESS[0] to $MESS[5].
• In a similar vein to the $MESS_n variables, subroutine calls of the form SetViewFromSearchFrame11($arg) and SetViewFromSearchFrame12($arg) don't look good either. The names suggest they have shared functionality: consider abstracting that functionality such that calls have the form SetViewFromSearchFrame($n, $arg).
• Look at perlop. Learn the difference between string and numerical relational and equality operators.
• Run widget and use the "See Code" buttons. There are sections for all different types of widgets; that includes a "Menus" section.
• See the Tk page. That has links to documentation about menus (and all other widgets).