sub CallDialog
{
    $testbox1->configure(-state=>'disabled');
###############################
# Added this line so the displayed value is correct
    $selected = $selected_1;  
###############################
    my $retval = $dialog->Show( -popover=>$form, -overanchor=>'c', -popanchor=>'c');

    if($retval eq "Cancel")
    {
        $testbox1->configure(-state=>'normal');
    }
    elsif($retval eq "Submit")
    {
        $testbox1->configure(-state=>'normal');
        $testbox1->setSelected($selected ); #(optional?)
    }
 
}

##</code><code>##

my $button = $form->Button(  -text=>"Dialog", -command=>sub{$selected=$selected_1;CallDialog($testbox1);} )->pack(-side=>'right');

##</code><code>##

use strict;
use warnings;
use Tk;
use Tk::JComboBox;
use Tk::Dialog;

my $form;
my %choices = (  'a'=>1,  'b'=>2,  'c'=>3 );
my $selected_1 = "a";
my $selected = "a";
my $dialog;
my $testbox1;
my $testbox2;

CreateMainForm();
MainLoop();


sub CreateMainForm
{
    $form = MainWindow->new();
    $form->title("Test for JComboBox Problem");
    $testbox1 = $form->JComboBox(  -textvariable=>\$selected_1,-validate=>'match', -mode=>'editable',-relief=>'sunken',  -highlightthickness=>0 );
    for my $x(keys %choices) { $testbox1->addItem("$x"); }
    $testbox1->pack(-side=>'left');    
    my $button = $form->Button(  -text=>"Dialog", -command=>sub{CallDialog();} )->pack(-side=>'right');
    
    $dialog = $form->Dialog (  -title=>"Part2 of test", -buttons=>["Submit","Cancel"],-default_button=>"Submit" );
    $testbox2 = $dialog->JComboBox(-textvariable=>\$selected, -validate=>'match',-mode=>'editable', -relief=>'sunken',-highlightthickness=>0);
    for my $x(keys %choices) { $testbox2->addItem("$x"); }

    $testbox2->pack(-side=>'left');
}

sub CallDialog
{
    $testbox2->setSelected($selected_1);
    my $retval = $dialog->Show( -popover=>$form, -overanchor=>'c', -popanchor=>'c');

    if($retval eq "Cancel")
    {
        $testbox1->configure(-state=>'normal');
    }
    elsif($retval eq "Submit")
    {
        $testbox1->setSelected($selected ); #(optional?)
    }
 
}