use warnings;
use strict;
use Tk;

my $mw = MainWindow->new();

my ( $var, $tvar );
my $opt = $mw->Optionmenu(
    -options => [
        [ jan => 1 ],
        [ feb => 2 ],
        [ mar => 3 ],
        [ apr => 4 ],
        [ may => 5 ],
        [ jun => 6 ],
        [ jul => 7 ],
        [ aug => 8 ]
    ],
    -command      => sub { print "got: ", shift, "\n" },
    -variable     => \$var,
    -textvariable => \$tvar,
)->pack;

# Now reconfigure the indicator button
$opt->configure( -indicatoron => 0 );

MainLoop;