Comment by jimbokun
5 hours ago
I have a very mild jolt of anxiety every time I want to enter a new line in Teams or Slack, wondering if it will send a half completed message I will need to edit after the recipient has seen the half completed message, or it will enter a new line like I want it to.
The behavior also changes if you start editing a numbered or unordered list. Maybe that enters the "formatting tools" mode you mention?
If you're worried about this, consider a copy and paste from notepad.
Your advice beautifully reinforces OP's case. We now have to use auxiliary apps with more predictable behaviour because designers made such a mess of things.
Note the "very mild" jolt, not quite enough to rise to the level of switching to Notepad (or Emacs in my case).