Beamer article

[CESAR MENENDEZ FERNANDEZ]

I'm afraid that the problem was with "\spanishdecimal{.}". I have just put the option "es-nodecimaldot" at document class, removing preamble lines and tags not appear.

-----Mensaje original-----
De: Jürgen Spitzmüller <spitz at lyx.org> 
Enviado el: sábado, 27 de febrero de 2021 13:12
Para: CESAR MENENDEZ FERNANDEZ <cesarm at uniovi.es>
CC: LyX User <lyx-users at lists.lyx.org>
Asunto: Re: Beamer article


> I'm sorry, but I don't know where log archive is located and the 
> compiled document has no errors.

Document > LaTeX Log (in LyX menu).

> Elsewhere I have just test to change language from Spanish to English. 
> Then I have errors in the preamble, so I comment preamble lines 
> %\selectspanish %\spanishdecimal{.} And now I get no tags!!
> output pdf document is OK!!

Why do you load babel and Spanish explicitly in the preamble? Just selecting Spanish as document language in LyX should suffice.
Anyways, this looks like a bug in babel-spanish. As I don't get it here, I suppose you need to update the babel-spanish package.

Best
Jürgen