[WP] Edit WordPress admin menu (backend) - Remove items/pages and sub-items/sub-pages, including Customizer

remove_admin_menu_items.php

<?php

// Remove items from menu for Editors
function remove_admin_menu_items() {
	if(current_user_can('editor') && !current_user_can('administrator')) {

		// Remove menu items
		// Tools
		remove_menu_page( 'tools.php' );

		// Remove submenu items
		// Appearence
		// Themes
		remove_submenu_page( 'themes.php', 'themes.php' );
		// Redirect Appearance to Menu editor
		$themes = stripos($_SERVER['REQUEST_URI'], 'customize.php');
		if ($themes !== false) {
			wp_redirect(get_option('siteurl') . '/wp-admin/nav-menus.php');
		}
		// Customizer
		$customizer_url = add_query_arg( 'return', urlencode( remove_query_arg( wp_removable_query_args(), wp_unslash( $_SERVER['REQUEST_URI'] ) ) ), 'customize.php' );
        remove_submenu_page( 'themes.php', $customizer_url );

	}
}
add_action( 'admin_menu', 'remove_admin_menu_items', 999 );

?>