Aaron D. Campbell

WordPress 3.3 introduced new flyout admin menus. If you prefer to be able to 
choose to have some menu items expanded this plugin will let you. Closed menu 
items still flyout. Open items are saved in a cookie, so while they persist, 
they don’t persist from browser to browser. JavaScript is required.

Expanded Admin Menus

Allows you to expand admin menus similar to WordPress 3.2

Luke Hertzler

Easily reorder your admin menu items on the user and blog level with simple drag & drop operation.
Menu ordering is automatically saved in the database by user and site.
Based on user, the plugin will load their own unique menu preference.
This plugin is a standalone feature of the <a href="https://wordpress.org/plugins/zeus-admin-theme/" rel="ugc">Zeus Admin Theme</a> plugin. To bundle this feature as well as ajax admin searching, hide admin menus, improved admin ui, and more download Zeus <a href="https://wordpress.org/plugins/zeus-admin-theme/" rel="ugc">here</a>

AJAX Admin Menu Editor

Works like a charm, and the footprint of this plugin is almost non-existent. This should be part of the core...

I can very easily tidy the backsite menu !

Easily reorder your admin menu items with simple drag & drop operation

Expanded Admin Menus vs AJAX Admin Menu Editor