Scroll jumping when back paginating

[lampholder]

Reported by @AmandineLP

Pagination is broken when I try to scroll back too quickly.

If I scroll back too quickly in a room, at some point (I assume when I reach the end of what is cached) the timeline only jumps slightly up and down, as if trying to find the right place to be. I have to wait several seconds to be able to start scrolling again.

[lukebarnard1]

Would be really useful to know which peripheral(mouse/trackpad)/OS/browser/version we're talking about here!

[AmandineLP]

Sorry I thought this was a rageshake. Using trackpad on my macbook air, in Chrome (64 today). I can show you IRL when I reproduce. I've been reproducing on several versions of Riot, and I think only e2e rooms

[lukebarnard1]

Oh my bad, I didn't see the ref to the rageshake.

[lukebarnard1]

trackpad on my macbook air

I have to say that I've witnessed the same on my Mac and I think the conclusion was that it would require a rewrite of our scroll component (ScrollPanel).

In short, the Mac fires scroll events at a very high frequency which makes it likely for one to fire immediately after a scroll jump has occurred - the panel then takes this incorrect position as truth because we save it.

[lukebarnard1]

This is related to #2646

[ara4n]

this is really sucking - i'm seeing jumps of several pages when I backpaginate.

[ara4n]

@lampholder says this has got worse since /experimental; for me it's got better. i'm going to investigate.

[lukebarnard1]

This is still quite bad for me. (Hello again btw! 😄)

I think my last thinking on it was that a potential fix would be chrome's scroll-anchoring becoming widely implemented in browsers. Although, they seem to be struggling with certain known bugs in the current implementation, namely a bug related to react-based infinite scrolling...

[ara4n]

this has been eclipsed by #8565