Cannot switch to forms containing "Private" fields

[pdestefanis]

If a form contains fields with restricted visibility, when the user attempts to switch to that form, the application shows the spinner next to the form selector, but the required form is never loaded.

If the default form has private fields, the fields are showed according to the logged-in user's role access level, but if the user switches to another form, and attempts to return to the default form, the same behavior is observed.

Field editability does not cause this issue, only its visibility level
This happens in both admin and member views

[srutto]

Confirmed on 2.6.1. The issue with the spinner seems to have been solved. the visibility level still affects the private fields. If a form has private fields, the fields are shown according to the logged in user's access level. Field edibility doesn't affect the fields.