Everything is in the title :
master.texfile contains several
- the indentation works in the master file but not in the subfiles. The TAB key acts like in LibreOffice.
The problem is likely that your other files use
tex-plain-mode instead of
.tex extension is used for both, so Emacs tries to guess, and it tends to err on the side of
You can add a
-*- mode: latex -*- somewhere on the first line of your files to avoid the problem.