use Tk;
use Tk::Text;

$mw = MainWindow->new;

$edit = $mw->TextUndo->pack;

$edit->insert('end', 't');

$edit->tagConfigure('<b>', -font => $mw->Font(-family => 'times', -weight => 'bold'));
$edit->tagConfigure('elide',  -elide => 1);

$tag = "<b>";

$mw->Button(-text => 'bold', -command => sub {
		$edit->insert('insert', 'de', [$tag, 'elide']);
		$edit->tagAdd($tag, 'insert');
})->pack;

MainLoop;