I don't know how to change its default size. From your screenshots, it appears that you know that one can manually adjust its size by dragging down on the corner. Somehow, I think that this size is varied by the type of activity where it is being used since more space is provided to ATTO in a forum. This could be good news. Maybe one can add some custom CSS to force its size in the Quiz activity.
Thank you for your reply/
Do you know what is the css custom code for changing the default so it will be larger by default for any multiple choice answer?
Thank you
I've succeed to solve it by adding the number 3 (it can be anything else too) here :
question/type/multichoice/edit_multichoice_form.php
around row 70:
$repeated[] = $mform->createElement('editor', 'answer',
$label, array('rows' => 3), $this->editoroptions);
.......
$repeated[] = $mform->createElement('editor', 'feedback',
get_string('feedback', 'question'), array('rows' => 3), $this->editoroptions);
