This is a good twitter feature that should be emulated :) It's very annoying to have to scroll all the way back up every time.
I agree, I find myself having to give up my place on my feed to access the menu very often. I'd also add that it'd be nice to have the sidebar bio info sticky positioned when scrolling on somebody's profile as well.
It also paves the way for the inevitable unlimited scrolling, be it 3rd party extension or 1st party feature.
Thirding this! Having it maybe be a floating corner menu?
This has been requested again here https://help.antisoftware.club/support/discussions/topics/62000183191