In some contexts, Moodle blocks file uploading, therefore disabling filepicker (or the Poodll buttons in you have Poodll Anywehre installed).
Examples of such contexts:
- comments to an answer in a quiz (mod/quiz/comment.php)
- assignment grading page (mod/assign/view.php?id=XXX&action=grader)
- grade editing page (grade/edit/tree/grade.php)
It's regrettable because it makes the feedbacks less rich, and feedbacks are the kind of information to which students pay the most attention.
Is there a way to circumvent this restriction to allow file upload form the text editor in any context ?