Enter on an empty trailing paragraph inside a container leaves it, the way
a second Enter leaves a code block. Without this a callout at the end of
the document traps the cursor: every Enter makes another paragraph inside
it and there is no way down to the document body.
The blank paragraph the user pressed Enter on is the escape gesture, so it
is carried out of the container rather than left behind as a stray line.
Enter on an empty trailing paragraph inside a container leaves it, the way a second Enter leaves a code block. Without this a callout at the end of the document traps the cursor: every Enter makes another paragraph inside it and there is no way down to the document body.
The blank paragraph the user pressed Enter on is the escape gesture, so it is carried out of the container rather than left behind as a stray line.