仅向超级管理员显示css

Question

My goal is to hide specific tables with CSS on WordPress dashboard, from all users except super admin.

<?php is_super_admin( $user_id ); ?>

add_action( 'admin_head', 'my_custom_function' );
function my_custom_function() {
 if ( ! current_user_can( 'update_core' ) ) {
   echo '<style>p.smush-status {
   display: none;
   }
   button.button.wp-smush-send  {
   display: none;
   }
   #smushit {
   display:none;
   }</style>';
 }
});

But, when I'm adding this code to mu-plugins, I got the following error:

Fatal error: Call to undefined function wp_get_current_user() in /home/.../public_html/domain.com/wp-includes/capabilities.php on line 1614

capabilities.php it's WordPress core file.

Would you please have a look and tell me how can I improve this code?

Thank you

Answer 1

Do not use css to hide part of the admin dashboard, this is a security breach. You must to unset it using a function added in your theme functions.php:

// Create the function to use in the action hook

function remove_dashboard_widgets() {


    global $wp_meta_boxes;

    // Remove the quickpress widget

    unset($wp_meta_boxes['dashboard']['side']['core']['dashboard_quick_press']);

    // Remove the incomming links widget

    unset($wp_meta_boxes['dashboard']['normal']['core']['dashboard_incoming_links']);
} 

// Hoook into the 'wp_dashboard_setup' action to register our function
if(!is_admin()){
add_action('wp_dashboard_setup', 'remove_dashboard_widgets' );
}

Edit: and dont edit wordpress core files aswell, you will lost everything because of update.