bug#16619: 24.3.50; REGRESSION: transparent *Completions* now

[Drew Adams <drew.adams@oracle.com>]

> Yep, it's a regression. Looking at the change list, it's still not
> clear to me what causes it, and I haven't tried to repro yet. It'd be
> helpful if you could come up with a minimum configuration delta
> (relative to emacs -Q) that triggers the issue.

OK, here is a pretty minimal recipe to repro from emacs -Q.

Use this as your startup command:
runemacs.exe -Q -l "onetest.el" -f "1on1-emacs"

And put this in file onetest.el:

----------------8<-----------------
(provide 'oneonone)
(require 'oneonone)

(defvar 1on1-minibuffer-frame-alist
  (list
   (cons 'font "-*-Lucida Console-normal-r-*-*-14-*-*-*-c-*-iso8859-1"
         ;; If use this instead then the problem goes away.
         ;; "-Misc-Fixed-Medium-R-Normal--15-*-*-*-C-90-ISO8859-1"
         )
   (cons 'height 2)
   (cons 'minibuffer 'only)))

(defun 1on1-emacs ()
  ""
  (interactive)
  (setq default-frame-alist (list (cons 'minibuffer nil)))
  (setq pop-up-frames  t)
  (setq minibuffer-frame-alist 1on1-minibuffer-frame-alist)
  (make-frame 1on1-minibuffer-frame-alist)
  (setq minibuffer-auto-raise t)
  (setq w32-grab-focus-on-raise nil))
----------------8<-----------------

After starting Emacs, do `M-x forw TAB'.  The *Completions*
frame is transparent.

And if you change the font, per the comment, then the bug
goes away.  This is on MS Windows, where I have font Lucida
Console installed.