[Q] text property on mode-line string

[Daiki Ueno]

(Sorry for this report not being sent using M-x report-emacs-bug.  I
haven't finished configuring email environment for GNU Emacs.)

I have a question about text property on mode-line string.  I wanted
to decorate a part of mode-line, so I simply set 'face property for a
string and placed the string at the beginning of mode-line-format:

  (setq test-face (make-face 'test-face))
  (set-face-foreground 'test-face "red")

  (push (propertize "ABC" 'face 'test-face)
        mode-line-format)

Of course it works, i.e. red "ABC" shows up on the left side of mode-line.

Next, I tried to use a symbol reference to the propertized string:

  (setq mode-line-format (nconc (list "" 'abc) mode-line-format))

And:

  (setq abc (propertize "ABC" 'face 'test-face))

It also works as expected.  Finally, I tried to use a list as the
value of abc:

  (setq abc (list (propertize "ABC" 'face 'test-face)))

It doesn't bring the same effect as above 2 cases.  i.e. "ABC" is not
displayed in red (on my environment, it displayed in black).  Oddly
enough, when I removed the 'face property from the first character
("A"), only "BC" is displayed in red:

  (remove-text-properties 0 1 '(face) (car abc))

Is this a bug?

I'm using Emacs 21.3.

Regards,
-- 
Daiki Ueno