The button to go up a folder in "materiale" does not work

[Tizio0o0o0o]

Describe the bug
The button to go up a folder in "materiale" does not work

To Reproduce
Steps to reproduce the behavior:

1. Go in a subject

2. Click on 'materiale'

3. Enter in a random folder (in my example I entered in 'Further_readings')

4. If you try to get out of this folder with the button on the right of the image

   

it bugs out and the only way to see a real folder again is to select it from the list of folders in the lefs side

[MarcAnt01]

I just would like to add that this bug has been present for years and it is very annoying, because folder navigation is one of the most frequent activities within the portal (from a student perspective)