Scrollable containers in shadow DOM are ignored if they are parents of the slots into which the target was slotted #916
Description
Hello!
I noticed this library doesn't work on elements that are slotted inside containers that are in a shadow DOM. Here's a simple case where you can see it doesn't work: https://codepen.io/remiscan/pen/ogNVOWQ
(And here's an equivalent case without the shadow DOM, that works: https://codepen.io/remiscan/pen/LEYavyg).
I'll make a pull request with a fix :)