please forgive me if this proves not to be a bug, but it seems to me clone(true) does not carry on the behaviour attached to cloned elements, or elements being child of cloned element.
no matter how i tried, it fails, as you can see it here:
http://www.pixeline.be/youplaboum/ui.html (fill the field "nombre de
semaines" with, say, "2" which will clone twice a small UI on change.
The datepicker behaviour in the cloned UI datefields do not work
properly, nor the masked plugin, nor Kelvin's datepicker. Even if i
redeclare the behaviour in the function called back when cloning is
done, fails.
if i do not specify the boolean, the bug disappears, but then, i must redeclare the behaviour after the cloning took place.
let me know if you need more info.