Form components disappear after selecting a rendering image then another one.

[ascobie]

Exists in Stable 17.3.0

1. Go to the add pool form
2. Select a rendering image
3. Change your mind and select a normal distro,
4. Rest of form components disappear

Note that when you select a rendering image again, the form items show up again .... must be something to do with the items on the form being hidden and re-shown affecting other bl-form-section components.