Hey @Prasant
thanks for your help.
I was eventually able to see the cornerstone edit in the incógnito window of Chrome.
In the meantime I have seen another updating of cornerstone and child theme and I did it. Then I have updated the IOS:
the result is the same.
At least I can still use cornerstone from the incógnito window.
But if you hane any idea on why I cannot see cornerston from regular browser I appreciate it.
if you wish to check it out, I will resend you the information
thanks a lot