As you can see in the clip below, the UI moves a bit weirdly when you filter lists by title because the scrolling bar disappears. But it’s not just that. It looks like you tried to account for that which is very nice (as there seems to appear a black bar on the right), but it doesn’t seem to be quite working.
Why would you need to scroll when you are filtering tho.
Can’t say I ever noticed because all scrollbars are hidden if I don’t use them. They’re the ugliest things in existence 
I think you kind of missed the point. It’s not about having a scrollbar there when you can’t scroll. It’s about the UI doing these movements first to the right and then to the left.