ScrollBar Problem!

hello guys!
Ihave this problem when i click on The Log in the scroll Bar disappears.
you can check the issue here

Looks like this is the default behavior with Bootstrap modals, you can see demo here:

notice that the page is long and there’s a scrollbar, but when you open up the modal the scrollbar disappears and you no longer can scroll the page

You can have the background body scroll by adding the following css property:
body.modal-open { overflow-y: auto }

Ooh right thanks.
but I still have a problem when I click on LogIn, all the width of the body change. Did you notice it!