Note input mode, esc once, esc twice

When I create a fresh new score, I'm not in note input mode, and voice 1 is selected.
In this "mode" (let's call it M for my question) clicking on symbol 8th note will change the first rest of the score and press key 'a' will enter a 8th 'a' replacing the rest + enter 'Note input mode' for me.
If I press 'Esc' once, I quit 'Note input mode' and I'm back in mode "M" in which, as Voice 1 is "on", clicking on symbol 8th or 16th has an influence on the score and pressing a key a, b, c, ... enters the 'Note input mode' again with a 8th or a 16th added to the score (replacing the rest).
But, if from this "M" mode I press Esc, the voice is unselected, and then clicking on symbol 8th or 16th has no influence at all on the score and pressing a key a, b, c, ... enters the 'Note input mode' with a quarter added to the score.

I have 2 questions:

-in the handbook I have not found yet mention of this "intermediate" "M" mode with the voice selected but not the real note input mode yet. What is it exactly?

-once I quit this "M" mode by Esc, I can't find any way to enter it again other than entering the "note input mode" and pressing Esc once. Is there any way to "activate" voice 1 again, without first going to full "note input mode"?

Thanks