Thanks a lot, Tim. I am saving those options to try them.

Ypo

Ypo <ypuntot@gmail.com> writes:

Thanks, Samuel

I've uninstalled fancy-dabbrev, and it seems to work when I complete using M-/. But, now I don't have candidates to choose the
completion. Any advice with this?

Best regards,
Ypo

You might want to have a look at the corfu and cape packages. 

https://github.com/minad/corfu
https://github.com/minad/cape

The corfu packages is basically a completions UI package built on-top of
built-in Emacs completion functionality while cape is a set of
completions at point functions which has support for dabbrv (and
others). 

Alternatively, if your a copmany mode user, I believe there are company
dabbrv modes you can install. Company is probably more mature in the
sense it has been around for some time. However, I like the underlying
principals of corfu (i.e. leverage of existing Emacs functionality
rather than re-inventing it). 

I did find with corfu and cape that it took a bit of experimentation and
use to get things 'just right'. However, once you have it working and
are use to it, I find it works well (I'm using Emacs 28 and 29(.