fix(MessagesList): prevent scroll position changes based on messages …

[DorraJaouad]

…height when user is scrolling down.

☑️ Resolves

• Fix "Scroll to bottom" does not scroll all the way #13237

🖌️ UI Checklist

🖼️ Screenshots / Screencasts

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🏚️ Before	🏡 After
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🏁 Checklist

• 🌏 Tested with different browsers / clients:
  • Chromium (Chrome / Edge / Opera / Brave)
  • Firefox
  • Safari
  • Talk Desktop
  • Not risky to browser differences / client
• 🖌️ Design was reviewed, approved or inspired by the design team
• ⛑️ Tests are included or not possible
• 📗 User documentation in https://github.com/nextcloud/documentation/tree/master/user_manual/talk has been updated or is not required

[DorraJaouad]

Just for the record:

While debugging I noticed other issues:

1. Scroll to bottom not completed sometimes: We have many things that can load while it is scrolling down, and from the time the scroll is triggered, the height has changed, so it will scroll to the previous height and not to post-loading height.
   Possible solution: recursive scroll position check to keep scrolling until bottom is reached

2. Scrolling through a long list of unread messages: When joining conversation and we have more than 50 unread messages, we don't actually fetch all of them, during scroll to bottom, we keep fetching, which leads to just scrolling through the initial batch, then user has to press scroll to bottom again to scroll to the next one.
   Possible solution: maybe the same as 1. ?

P.S: we need a summary of scroll handling there so we stay aware of restrictions and limitations :')

[SystemKeeper]

I think we have the same problem when you click on a quote an we have to scroll upwards ?

[SystemKeeper]

I think we have the same problem when you click on a quote an we have to scroll upwards ?

It also happens when you open a link to a message and we try to scroll to that message. We end up "somewhere near" that message in most cases.

[Antreesy]

With 917358d in mind we can use current direction to decide, whether we perform this additional scroll up/down or not