bug#3195: 23.0.93; Shrinking frame with GTK+ tool bar in KDE with gtk-qt engine

This bug was reported and discussed some time ago in emacs-devel; see
the thread around <http://thread.gmane.org/gmane.emacs.devel/83390>.
The purpose of my report now is mainly to put it into the bugtracker (I
was prompted to do this now by Jan D.'s conclusion that there is no
workaround within Emacs for bug#3145).  For convenience, here is a
simple recipe to show the bug and some additional information:

1. Start emacs -Q in the KDE desktop (versions 3.5.10 and 4.2.2 both show
   the bug, though differently, see below), using the gtk-qt engine with
   the them QtCurve.  The icon set may also make a difference; I'm using
   the default icons provided by openSUSE 11.1 in KDE 3.5.10 and Oxygen
   in KDE 4.2.2.
2. M-: (frame-height) => 40
3. C-h i
4. M-: (frame-height) => 40
5. M-: (frame-height) => 39
...
n. M-: (frame-height) => 39-n+5

If the tool bar is disabled or detached, the frame does not shrink.

In the post referred to above, Jan D. asked what version of gtk-qt and
GTK theme I was using.  Then as now I use the current versions from the
openSUSE repositories; these are the RPMs kcm_gtk-0.7svn20070827-138.7
for KDE 3.10.5 and kde4-kcm_gtk-1.1-131.8 for KDE 4.2.2.  I also use the
openSUSE default gtk-qt theme, QtCurve, in both desktops.  However, for
this updated report, I did try some other GTK themes.  In KDE 3.5.10,
the the Clearlooks theme (or style, as it is called in openSUSE) does
*not* show the bug, i.e. at step 5 and further above, frame-height
remains at 40 lines.  I still haven't tried other GTK styles in KDE
3.5.10.  However, in KDE 4.2.2., the bug happens regardless of which GTK
style I choose (this may be a bug in KDE 4.2.2. or in the gtk-qt engine
it uses).

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