Confusing thread UI with side replies

Hey there, phanpy is fantastic. You have a very good taste for simplicity in UI, I really like the choices you make in this client.

One tiny thing I think is a bug: I got confused by the vertical bar showing thread responses in the Notifications display.


mhoye posted a megathread, replying only to himself. I've started the screenshot at message 9/X of his. I (nelson) responded to message 7/X, but Phanpy makes it look like it's a reply to 9/X. Then posted a 10/X replying to his 9/X. But phanpy put a vertical bar between my message and his 10/X, making it look like his 10/X was a direct reply to mine. It wasn't, it's a direct reply to 9/X.

Here's a [link to his 7/X post](https://mastodon.social/@mhoye/111336097458684403). Note that I deleted and reposted my reply after taking this screenshot, so what's on the public timeline now is slightly different from this screenshot. I think it's still confusing though.

My guess is the logic to display threads is doing something a little wrong with replies to long threads. It gets a little confused as to what is replying to what. This data is all pretty tricky, I'm not sure how to sort it out other than a bunch of test cases.

Start by reproducing the Notifications view from the screenshot with a long self-replying thread and an intervening reply. Trace how the thread display determines reply relationships and add test cases for replies to earlier posts. Done means the vertical bar appears only when the displayed post is a direct reply to the post it visually follows.

Written by the indexing model from the issue text.