Jcrop suddenly jumps to the page

here is my page: http://anashimyafim.co.il/join

you can click the green button below, you will be bound to another div where you have to upload the image.

than after loading the image, I put it on the page and call the jcrop function.

than if I clicked on an image to crop it, divs move suddenly.

Do you have any suggestions?