dialog + draggable and dialog + draggable + judder

dialog + draggable and dialog + draggable + judder

firstly does anyone now how to change the axis property on a dragable dialog
assumed it would be either of the following

$('#MyDialog').dialog().draggable('option','axis,'x');

or

$('#MyDialog').draggable('option','axis,'x');

however i have no luck with either.

anyone come across this before?