Good Morning guys!

I want to be able to unflatten a mirror part, but I can't.

So, I know that I need the "Sheet Metal Info" active, but with some pieces I can't, because you can see at the picture the option is suppressed.

And with other pieces I can, like the picture shows.

Why for some parts I can select the option?

Depends for the features that the part has?

Thanks in advance!

P.D Find the attachment with some of my files where I have this situation