Is Hide/Show available for formula fields?

Is Hide/Show available for formula fields?

We're desiring to conditionally hide/show a set of fields, 2 of which are formula fields.

All is OK except for the formula fields.

The editor refuses to save, unless we comment out the 2 formula fields.
The error is "Hide function cannot be applied for <fieldname>".   And, "Show function cannot be applied..."

These 2 fields have the "Show on Form" option selected, because we DO want them to show on the form.   ...Unless they are hidden with the set of fields.

(I am using the Deluge names for the formula fields, even though they are not exposed in the form builder UI -- I learned them from the .DS file.)

So how can we hide/show formula fields?
Thank you!