Double scrollbar appears on the website

This problem will be caused by the  Force full width option. This option is calculating the size of the slider using javascript, but that can't be pixel perfect, this is why we put an overflow hidden on the website, when this option is turned on, to avoid horizontal scrollbars. But if you have a css code like this in your website:

html, body {     
     height: 100%; 

then browsers are handling this weirdly, causing double scrollbars. So you should either turn off the force full width option, or find the height css code, and remove that instead.