Sidebar Mobile Menu (Smartphone + iPad)

Hi Team,

since the last update a sidebar menu appears on mobile devices and iPad when manually or accidently scrolling to the right. You can see it on my webiste: http://www.webigami.de (resize the browser to mobile view an then scroll to the right):

With this code, you can deactivate it on Smartophones:

@media only screen and (max-width: 767px){
    #wrap_all {
        position: relative;
    }
}

How can I do it on iPads landscape and portrait? And still: Why does it appear all of a sudden??

Thank you,
Jan