Enable Drag & Drop reordering by default in SilverStripe (2.3.2 or higher)

gistfile1.php

<?php
# For the truly lazy (like myself) -- By Louis St-Amour
#
# A quick script to enable drag & drop reordering by default.
#
# To install:
#   1. Name this file MyCMSDecorator.php in mysite/code
#   2. Requires DataObject::add_extension('LeftAndMain', 'MyCMSDecorator');
#      in mysite/_config.php
class MyCMSDecorator extends LeftAndMainDecorator {
	
	function init() {
		Requirements::javascript('jsparty/prototype.js');
		Requirements::customScript(
		   'DragByDefaultAction = Class.create();
			DragByDefaultAction.applyTo(\'#sortitems\');
			DragByDefaultAction.prototype = {
				initialize: function () {
					this.checked=true;
					$(\'sitetree\').makeDraggable();
				}
			}'
		);
	}

}
?>