mode
two ways to see a suggestion. the difference is how much you want to choose.
chat mode (default)
you get two rows: fix, your message with the errors corrected and nothing else touched, and native, the same message rewritten the way a fluent speaker would say it.
changed words are marked in red so you can see exactly what moved. press tab to accept the highlighted row, or ↑ ↓ to move between them first.
use chat mode when you are still learning. seeing the fix next to the rewrite is where the learning happens.
flow mode
one row, the best suggestion, nothing to compare. press tab and keep typing.
use flow mode when you already write well and just want the friction gone.
the why button
in chat mode the popup has a ? that explains the fix in one line: which rule you hit, and what to do next time. it is off when you are reading replies or translations, where there is no fix to explain.
turn it off entirely in settings under features, if you want suggestions without the lesson.