double-width characters in tables

[Eric Abrahamsen <eric@ericabrahamsen.net>]

This problem has been flagged up before:

http://orgmode.org/worg/org-issues.html#mid-87pqt04qg1-2Efsf-40gmail-2Ecom

It's causing me headaches at the moment, so I'm trying to see if I can
find a solution.

The proximate cause of issues with double-width characters in table
fields (they also mess with justification) is that the contents of the
fields are propertized with a length based on `length', and not
`string-width'. So you get this:

#("《蛙》" 0 3 (fontified t line-prefix #("    " 0 4 (face org-indent))
 wrap-prefix #("    " 0 4 (face org-indent)) face org-table))

3 is the number of characters in the string, but it takes up 6 columns
of screen width. That messes up justification.

I can't for the life of me figure out where that number is getting added
to the string! I tried changing `length' to `string-width' in all manner
of org functions, such as `org-add-props', but could never get that
number changed during the fontification of the org tables.

I wouldn't be surprised if this is something outside of org, or if
"fixing" it would lead to more troubles, but does anyone have any ideas
about this? Fixable, or not?

Thanks!
Eric