winning.php

<?php

class Post extends \WPUF_Add_Post {
    function __construct() {
        remove_shortcode('wpuf_addpost');
        add_shortcode('wpuf_addpost', array($this, 'shortcode'));
    }

    function post_form($post_type) {
        $reflection = new \ReflectionMethod('WPUF_Add_Post', 'post_form');

        $file = file($reflection->getFileName());

        $content = implode(
            '',
            array_slice(
                $file,
                $reflection->getStartLine(),
                $reflection->getEndLine() - $reflection->getStartLine() - 1
            )
        );

        $content = preg_replace(
            '#wp_dropdown_categories\( \'#',
            'wp_dropdown_categories( \'selected=' . get_user_option('default_category'). '&',
            $content
        );

        $content = str_replace('$this', '$that', $content);

        $post_form = create_function('$that, $post_type', $content);

        return $post_form($this, $post_type);
    }
}