filters not shown [SOLVED WAS PERMISSION ISSUE]

In the "frontend" each teacher sends a note to a group of students. Each student has a category, a type and a template.
Each student can see his notes, sent by differents teachers, visiting their category.
But there is one template, one type and one category for al the notes, only accessible to teachers and management, containing all the notes sent by all teachers of the whole group of students.
It is in this category must have a filter to select one subject at a time, but using the filter should appear all subjects of all teachers.
Regards

Hello
I use flexicontent 1.5.4
I created a field type "select" on a form in the "frontend".
I want to hide some options of this field to a registered user.
I can use the "Add css to edit form" to do that?
What is the syntax for that?

Regards