Description
I've long found the scrollbar annoying - it's basically showing me 'how many messages are paged into memory' and my position within that list, which doesn't actually map onto a particularly useful mental model.
Slack it seems tries to represent the scrollbar as if the whole of room history were already paged in - resulting in a useful indicator of the scale of the room and my position within it (albeit one that jumps around like anything as it tries to keep itself accurate as more real messages are loaded in).
I understand this would be tricky for us - I think it's computationally expensive to calculate the size of a maximum timeline my user might have access to.
What if we did away with the standard scrollbar entirely? I like the idea of spooling old-school printer paper - some visualisation along oneside to indicated scrolling movement, but without speaking to your specific position within the whole. There could be indicators for when you're near the top or the bottom of your visible room history.