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

[martin rudalics]

> 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.

Thanks for the excellent recipe.  I checked in a fix for this in
revision#116242.

I'm afraid that I haven't understood the processing of frame parameters
yet.  All I can do is fixing problems by trial and error.  This
particular bug crept in when I tried to fix Bug#16529.  And Bug#16529
was a consequence of attempting to fix Bug#16051. So if someone wanted
to have a look into this ...

martin