Why is it failed to unhide fileds "Cookies" in Field Management?

[Alan_Lai]

I could unhide all other hidden fields successfully, except "Cookies".
Every time I unhide it, it just re-hidden itself automatically when I refresh the page.

[SanfordWhiteman]

It's forcibly hidden in the UI AFAIK. What do you need it for exactly on the UI side? Note it would always be read-only even if shown.