use Tk;
use strict;

$::cini_global = { trickle => { email_template_file => "nothing" }}; 

my $mw = MainWindow->new;

$mw->Entry(
   -width => 40,
   -textvariable => \$::cini_global->{trickle}->{email_template_file}
)->pack(qw/-expand 1 -fill x/);

$mw->Button(
   -text => "Change",
   -command => sub {
      $::cini_global->{trickle}->{email_template_file} =
         $mw->getOpenFile();
})->pack;

MainLoop;

##</code><code>##

[trickle]
email_template_file=nothing

##</code><code>##

use strict;
use Config::IniHash;
use Data::Dumper;
use Tk;

$::cini_global = ReadINI 'config';
my $ref = $::cini_global->{trickle}->{email_template_file};

my $mw = MainWindow->new;

$mw->Entry(
   -width => 40,
   -textvariable => \$ref
)->pack(qw/-expand 1 -fill x/);

$mw->Button(
   -text => "Change",
   -command => sub {
      $ref = $mw->getOpenFile();
      $::cini_global->{trickle}{email_template_file} = $ref;
})->pack;

MainLoop;