Same thing with *info* windows.

I think it has to do with this (from `C-h v mode-line-buffer-identification'):

Mode line construct for identifying the buffer being displayed.

Its default value is ("%12b") with some text properties added.

Major modes that edit things other than ordinary files may change this

(e.g. Info, Dired,...)

I'll take a look later, when I get some time. Thanks for the report.

Hi José. No, I don't know why. I'll take a look (later). I confirm that I see the same thing. Dunno why Dired windows would be an exception.

I just noticed that the library doesn't seem to work on the dired buffer, on other buffers it does seem to work well. Do you know what could be the cause?

See library `modeline-win.el'.
Does it do what you're looking for?

It highlights the buffer name in the
mode-line for the selected window.

That is, whichever window is currently
selected, its buffer name in the mode
line is highlighted (using face
`mlw-mode-line-buffer-id-selected-window').

The code is here:
https://www.emacswiki.org/emacs/download/modeline-win.el
It's just a few lines of code.