bug#3243: 23.0.93; display problem with default resize-mini-windows

1. emacs -Q
2. M-x customize-face RET mode-line RET, then set the height attribute
   to a scale value of 1.3 (the problem described in step 4 may depend
   on the font used; if it does not appear with this scale value, it
   should with a larger one).
3. For this step, you need to have at least two files in a directory,
   whose names are in a substring relation to each other, e.g. file1,
   file12.  Further, either the file names themselves or the path+file
   names must be long enough so that when inserted by completion after
   the dired prompt, the string is almost as long as the window is wide,
   but not so long as to induce line wrapping in the minibuffer.  Now
   type: `C-x d' and at the prompt enough of the file names (or
   path+file names) so that when you type TAB, you get the message
   "[Complete, but not unique]".
4. Note that the latter message wraps, forcing the minibuffer to grow.
   After the message disappears, the minibuffer retains its increased
   height, due to the default setting of resize-mini-windows, grow-only.
   The display problem is in the *Completions* buffer: the file names
   are displayed in a single column (at least with only two or three
   files), and the last file name is slightly hidden by the enlarged
   mode line.  (If resize-mini-windows is set to t, the last file is at
   first hidden, but when the message disappears, the minibuffer shrinks
   again and the last file name is displayed completely.)

This is a regression with respect to Emacs 22.  There, the *Completions*
buffer displays even just two file names in two columns, and regardless
of how high the mode line is, it does not obscure the last file name.


In GNU Emacs 23.0.93.1 (i686-pc-linux-gnu, GTK+ Version 2.14.4)
 of 2009-05-03 on escher
Windowing system distributor `The X.Org Foundation', version 11.0.10502000
Important settings:
  value of $LC_ALL: nil
  value of $LC_COLLATE: nil
  value of $LC_CTYPE: nil
  value of $LC_MESSAGES: nil
  value of $LC_MONETARY: nil
  value of $LC_NUMERIC: nil
  value of $LC_TIME: nil
  value of $LANG: en_US.UTF-8
  value of $XMODIFIERS: @im=local
  locale-coding-system: utf-8-unix
  default-enable-multibyte-characters: t