使父菜单项和子菜单的slug相同(第一个菜单项),如下所示
function actions_recent_bids_add_admin_page(){
add_menu_page(\'Recent Bids\', \'Auction Reports\', \'manage_options\',\'wc-auction-reports\',\'actions_recent_bids_list\',\'dashicons-chart-area\', 56);   
  
add_submenu_page(
    \'wc-auction-reports\',               // parent slug
    \'Recent Bids\',                      // page title
    \'Recent Bids\',                      // menu title
    \'manage_options\',                   // capability
    \'wc-auction-reports\',               // slug
    \'acutions_customers_spendings_list\' // callback
); 
add_submenu_page(
    \'wc-auction-reports\',               // parent slug
    \'Customer Spending\',                // page title
    \'Customer Spending\',                // menu title
    \'manage_options\',                   // capability
    \'wc-acutions-customers-spendings\',  // slug
    \'acutions_customers_spendings_list\' // callback
); 
 
add_submenu_page(
    \'wc-auction-reports\',          // parent slug
    \'Customer Bids\',               // page title
    \'Customer Bids\',               // menu title
    \'manage_options\',              // capability
    \'wc-acutions-customers-bids\',  // slug
    \'acutions_customers_bids_list\' // callback
);  
}
add_action(\'admin_menu\',\'actions_recent_bids_add_admin_page\');