Reply To: WP Default Search Not Getting Replaced.

[Ernest Marcinko]

May have been an error there, try this:

add_filter( 'generate_navigation_search_output', function() {
    return sprintf(
        '<div class="navigation-search">%s</div>',
        do_shortcode( '[wpdreams_ajaxsearchpro id=2]' )
    );
} );