tentatively fixes #776

[correabuscar]

or perhaps there's a better/different way?
#776

[gyscos]

I think we could exit early from these functions if we notice at the start that self.children.is_empty() - there is no need to scroll, and there is no event we could react to.

[correabuscar]

I think I avoided early exit via 'if' check to avoid paying the check for every normal non-empty case, which should be most of the cases. At least, that's what I told myself at the time :)

feels kinda hacky either way, maybe I wait for someone else to do it better