@DiapDealer
Please believe me, I don't intend to strech the truth
and sorry if I give you this feeling. I selected an option so as Sigil does nothing on opening an EPUB because of some Doctype issues I had reported about.
I did not invent this message from Sigil. OK next time, I'll send you a PM if you find my messages too unpleasant. Meanwhile, I will try to reproduce this.
Cheers