The core problem is that `$(this).attr('checked')` on lines 63-64 will return `undefined` if the attr is not set, and that `$(this).attr('checked', undefined)` does not result in the checkbox becoming unticked. Similar with 'disabled'.

It's probably better to use the `is` with the ':checked' pseudoclass, and then set the property of the checkbox with `prop`. Something like that:

				if(this.is(':checked')) {
					checkboxes.each(function() {
						$(this).data('SecurityAdmin.oldChecked', $(this).is(':checked'));
						$(this).data('SecurityAdmin.oldDisabled', $(this).is(':disabled'));
						$(this).prop('checked', true);
						$(this).prop('disabled', true);
					});
				} else {
					checkboxes.each(function() {
						$(this).prop('checked', $(this).data('SecurityAdmin.oldChecked'));
						$(this).prop('disabled', $(this).data('SecurityAdmin.oldDisabled'));
					});
				}