On Tue, Mar 26, 2019 at 10:27:21PM +0100, Sebastian Urban wrote:
> Hello,
> 
> I'm beginner in the world of Emacs and I have a problem with
> disappearing 'table-cell' face in Text-based Tables [...]

> Is this normal behaviour, do modes with syntax highlighting
> override(?) faces from other environment like table?

(For some reason I don't manage to get table-cell face to bear
in my setup, so I can't double-check what I am talking about.
So take with two fists of salt)

It's quite possible that font-lock is obliterating your table-cell
face. To perhaps get an idea of what's going on, just move point
to one of those character positions you think should be fontified
differently and do M-x describe-char. You'll get a description
of the character at point, but also of the properties and overlays
at this position, including the faces and their priorities.

Cheers
-- t