Why is tab unaffected by font whereas space is affected?

[Richard Wordingham]

On Mon, 20 Apr 2020 13:48:09 -0700
Asmus Freytag via Unicode <unicode at unicode.org> wrote:

> But generally, in rich text environment, these are properties of
> blocks of text (paragraphs) and don't track with font size.

Surely the primary target of a text editor is plain text.  This is why
one would expect differences between a word processor and a program
editor.  Of course, with a proportional width font, it is rather
difficult to interpret a tab position of '8 characters'.  Interpreting a
unit of 'character' works if tab characters are only used for
indentation.  It doesn't work so well if it is used to separate data in
a table.

Fixed width fonts for multilingual data tables are not necessarily
available, though Evertype provides a wide coverage for a sane but not
universally adopted definition of 'fixed width'.

Richard.