//this.ModBox is an element with id=this.options.id
//after the first toggle() i can remove the element with the esc-key, but the document.removeEvent('keyup') doesn't kill the Event
//a document.removeEvent('keyup') in the console helps...

    ...
    toggle: function(){

        ($('overlay')) ? $('overlay').remove():this.overlay.injectInside(document.body);
        if ($(this.options.id))
        {
            $(this.options.id).remove();
            document.removeEvent('keyup');
            alert('asdf');
        }
        else
        {
            this.ModBox.injectInside(document.body);
            document.addEvent('keyup', function(event) {

                if (event.key == "esc")
                {
                    this.fireEvent('onSuccess', false);
                    this.toggle();
                }
            }.bind(this));
        }

    }
    ...