1. Navigate to the ch3-hide-menu-item folder of the WordPress plugin directory of your development installation.
2. Open the ch3-hide-menu-item.php file in a text editor.
3. Create a new PHP code file called ch3-hide-menu-item-admin-functions.php in the same directory and open it in a text editor.
4. Move the calls to the add_action function and the definition of the ch3hmi_hide_menu_item function to the new file, preceded by a standard PHP open tag and checking for the definition of a constant:

<?php

if ( !defined( 'ch3hmi' ) ) {
    exit;
}

5. Back in the main plugin code file (ch3-hide-menu-item.php), add code that will define a constant and check whether the current page being rendered is an administration page and proceed to load the administration functions if it is:

define( 'ch3hmi', 1 );

if ( is_admin() ) {
    require plugin_dir_path( __FILE__ ) .
        'ch3-hide-menu-item-admin-functions.php';
}

6. Save and close the plugin file.
7. While the plugin will continue to work as it did before, the action hook registration code will only be processed when an administration page is displayed.