Cannot save metaboxes position in a WordPress plugin

I'm developing a WordPress plugin that presents a kind of dashboard, full of custom metaboxes. I was able to get the open/hide/close and drag handles working properly; however these screen customization are not saved: when I reload the page, everything goes to default config (actually, all metaboxes opened and sorted following the add_meta_box order in code).

I added this nonce code to my admin page, but nothing changes:

                <form action="" method="">
     开发者_运维技巧               <?php wp_nonce_field('dice-roller-metaboxes-settings'); ?>
                    <?php wp_nonce_field('closedpostboxes', 'closedpostboxesnonce', false ); ?>
                    <?php wp_nonce_field('meta-box-order', 'meta-box-order-nonce', false ); ?>
                    <input type="hidden" name="action" value="save_dashboard_settings" />   
                </form>

Did I perhaps forgot something else?

you need to add some javascript to the bottom of the page that shows the metaboxes to handle the ajax save of the positions

    <script type="text/javascript">
            //<![CDATA[
            jQuery(document).ready( function($) {
                // close postboxes that should be closed
                $('.if-js-closed').removeClass('if-js-closed').addClass('closed');
                // postboxes setup
                postboxes.add_postbox_toggles('<?php echo $hook; ?>');
            });
            //]]>
     </script>

be sure to change $hook in the add_postbox_toggles line to the correct value for the page you're on