Search field for categories, multiple selections and savable defaults

I’m editing a page and it is difficult to scroll through the list as sometimes it refreshes. Can you fix this bug? It would be really useful if there was a search box as well and we could select multiple categories. I can directly edit the block.php file to get the defaults working, all except the random option that doesn’t seem to work. Can you add defaults so we can choose them from the settings page as well please?

$attributes = apply_filters(
		'flex_posts_attributes',
		array(
			'title'           => array(
				'type'    => 'string',
				'default' => '',
			),
			'title_url'       => array(
				'type'    => 'string',
				'default' => '',
			),
			'layout'          => array(
				'type'    => 'number',
				'default' => 2,
			),
			'post_type'       => array(
				'type'    => 'string',
				'default' => 'post',
			),
			'cat'             => array(
				'type'    => 'string',
				'default' => '',
			),
			'tag'             => array(
				'type'    => 'string',
				'default' => '',
			),
			'order_by'        => array(
				'type'    => 'string',
				'default' => 'Random',
			),
			'number'          => array(
				'type'    => 'number',
				'default' => 24,
			),
			'skip'            => array(
				'type'    => 'number',
				'default' => 0,
			),
			'exclude_current' => array(
				'type'    => 'boolean',
				'default' => true,
			),
			'show_image'      => array(
				'type'    => 'string',
				'default' => 'all',
			),
			'image_size'      => array(
				'type'    => 'string',
				'default' => '',
			),
			'image_size2'     => array(
				'type'    => 'string',
				'default' => '',
			),
			'show_title'      => array(
				'type'    => 'boolean',
				'default' => true,
			),
			'show_categories' => array(
				'type'    => 'boolean',
				'default' => false,
			),
			'show_author'     => array(
				'type'    => 'boolean',
				'default' => false,
			),
			'show_date'       => array(
				'type'    => 'boolean',
				'default' => false,
			),
			'show_comments'   => array(
				'type'    => 'boolean',
				'default' => false,
			),
			'show_excerpt'    => array(
				'type'    => 'boolean',
				'default' => false,
			),
			'excerpt_length'  => array(
				'type'    => 'number',
				'default' => 15,
			),
			'show_readmore'   => array(
				'type'    => 'boolean',
				'default' => false,
			),
			'readmore_text'   => array(
				'type'    => 'string',
				'default' => '',
			),
			'pagination'      => array(
				'type'    => 'boolean',
				'default' => false,
			),
			'align'           => array(
				'type'    => 'string',
				'default' => '',
			),
			'block_title_el'  => array(
				'type'    => 'string',
				'default' => '',
			),
			'post_title_el'   => array(
				'type'    => 'string',
				'default' => '',
			),
			'className'       => array(
				'type'    => 'string',
				'default' => '',
			),
		)
	);

The page I need help with: [log in to see the link]