BuddyPress adding some widgets meant to use for BuddyPress related informations but those widgets are unnecessary for sites in MultiSite unless BuddyPress multiblog is enabled.
add_action( 'bp_include', 'firmasite_bp_include_remove_widgets', 5 ); // priority is crucial function firmasite_bp_include_remove_widgets() { if ( !bp_is_root_blog() && !bp_is_multiblog_mode() ) remove_all_actions( 'bp_register_widgets' ); }
Thanks @geminorum and @BoweFrankema for inspiring this code snippet.