Microsoft Teams is now a complete meeting and calling solution

Sorry to continue to harp on about this, but the UI chat client is not yet good enough. There are basic UI defects which have been pointed out at length on the UserVoice forums, and which still need to be fixed.

There is no compact mode, despite it being the #1 UI request and having been in "working on it" status since February last year. Not even any ETA, or indication of what is being worked on. This despite at least three people in the forum thread independently hacking the web-client's CSS to prototype a compact layout, in a matter of hours each time. It is hard to avoid the conclusion that this is in fact not being worked on at all.

There is no multi-window support.

The threaded conversation UI is an anti-pattern, leveraging the user's existing knowledge of how chat clients work, and turning it against them so that they regularly create new conversations instead of following-up on the one they are reading. Compounding the problem, there is no way to correct this mistake once it has been made.

Putting the search bar in the window title bar also goes against ingrained behavior patterns for Windows users. It doesn't even save any space, as the conversation title (which is not interactive) is placed in the window client area. It would be much friendlier to swap these two controls, so that the title bar retains its standard role as a title and drag handle.