The scroll-to-bottom button is overlapping UI
The pictured button obscures chat contents, and stands graphically as the only round button and the only UI element which does not move when its container is scrolling (I've never seen that aywhere else within GNOME, or KDE for that matter).
In my experience is not very useful (I never had a need to click it), even more so when scrolling to see history is broken #269 (closed)
Fractal git c5a90d9a , gtk3-3.22.26-2.fc27.x86_64