Modal Background Scoll

Admittedly, this is less of a beta issue and more of a general question about modal functionality. Is there really no way to easily disable background scrolling? Working on a design that would require some scrolling in the modal window (similar to apple’s example in screenshot attached) but users are accidentally scrolling background and thinking it isn’t working…

Is it the content modal? Even if the mouse is outside the modal, it should still scroll the modal content until the end of the content is reached. After that it defers scrolling to parent elements (like the page body).