BuddyPress.org

@mr-bronze

You could try putting the following in you child theme functions.php file
function bbg_enqueue_styles() {
remove_theme_support( 'bp-default-responsive' );
}
add_action( 'wp_enqueue_scripts', 'bbg_enqueue_styles', 5 );

For more info ( including important details ) see:…[Read more]

@mr-bronze answered you at https://buddypress.org/support/topic/upgraded-and-now-nav-and-sidebar-is-responsive/

@mr-bronze see Boone’s answer in the link Aces gave –
“call it *after* bp-default registers theme support (after_setup_theme, 10) and *before* the stylesheet is enqueued (wp_enqueue_styles, 10)”