For a project I need to provide some computers with libreoffice running in kiosk mode. I need the libreoffice writer app on fullscreen all the time, and that users can create, open or modify files on his/her home only.
I know everything regarding file permissions and that the user won't be able to modify or create files outside of the home or /tmp directories, but to remove confusion (expected users are computer/linux illiterates), I'd like to (at least) make difficult to them to go outside the user folder. I don't care if the user really can go outside of his/her home folder, but I don't want it to be easy.
Just hiding the sidebar and changing the navigation bar in the file dialogs to not show anything above the user home directory is enough. I include a screenshot with notes of what I need.