A possible solution to 'Jump to first unread message' being useless

[ara4n]

This was kinda proposed by @richvdh when we first implemented it, but i think i just thought of a UX that would work.

We could track sparse ranges of read messages (and thus individually track the read state of individual messages) rather than the current high & low water marks. And we could then show this with a bar down the side of the timeline which quickly fades away to show when the app believes the user has read the messages - giving an effect bit like ink being exposed to sunlight for the first time and rapidly evaporating.

This would be a really fun interactive dynamic effect, and make it very clear where 'jump to first unread' would take you to - the beginning of the last block of unread messages as determined by that bar. It could then also give a nice UX for resetting the read state of a message (or room, or page of messages) as per bug #6482 (aka element-hq/element-meta#347) - you could have a context menu option for "mark unread after this point", which would 'fill the bar' back in (unless you re-scroll through the messages, at which point the bar would once again be marked as read).

Think of it as similar to unread state on email messages and it makes a little more sense. This would also then be useful for bridging to email and preserving the read/unread semantics that users expect there"

[ara4n]

https://github.com/vector-im/riot-web/issues/4134 is the main bug for fixing the jump to unread message banner.