Don't make other sections of the UI disappear when scrolling in one section

[Powersource]

Vague title but trying to say we should probably add scroll bars to the tree and the details view. Right now when you e.g. scroll far down in the tree you can't see the details anymore.

Might make sense to at the same time fix the mobile UX around this, not having the tree above the details but having it in a menu that you open from the top bar (and the top bar follows with you as you scroll in the details)