How to remove Help tab and the Dashboard widget area's empty border

Question

I only need to know using code in my functions.php, how to remove the Help tab and the widget border when it's empty.

I found answers here but they were old and things have changed. I'd like an updated solution to this problem, if there is one.

Screenshot:

By the way, I have removed the Screen Options using this code:

function remove_screen_options(){
    return false;
}
add_filter('screen_options_show_screen', 'remove_screen_options');

What do I need to do to remove the Help Tab and the Dashboard widget borders?

Answer 1

The code below will remove the Help Tab and will hide the extra two Dashboard widget areas:

add_action( 'admin_head', 'wpse209151_dashboard_cleanup' );
function wpse209151_dashboard_cleanup() {
    $screen = get_current_screen();

    // Bail if we're not looking at the dashboard
    if ( 'dashboard' !== $screen->base ) {
    return;
    }

    // Deal with the Help Tabs
    $screen->remove_help_tabs();

    // Hide the desired Dashboard widget areas 
    // 4 available widget areas: #postbox-container-1,2,3,4
    echo '<style>
        #postbox-container-3,
        #postbox-container-4 {
            display: none;
        }
    </style>' . "\n\n";
}