use Tk;

$main = MainWindow->new();

$main->Button( -text => "Click Me!",
    -command => \&display
)->pack(-side => "left");

$text1 = $main->Text ('-width'=> 40, '-height' => 2
)->pack;

$text1->bind('<Double-1>', \&display);

sub display
{
    $text1->insert('end', "Hello!");
}

MainLoop;