Re: Incorrect TAB width

[Richard Stallman]

This is an important problem, and I think we need to fix it.  I cannot
reproduce it myself, since I don't have a new version of X.

It surprises me that any any version of X can tell whether the Emacs
buffer contains tabs or spaces.  Emacs handles tabs by displaying
spaces (or at least, it used to); by the time the X server gets
involved, there should be no difference.  If Emacs even looks
at the fonts' width for tab, that seems to be a bug.

So if you can find out where Emacs even pays attention to what the
font says or does for a tab character, that should be a start at
debugging this problem.