bug#23568: 25.0.94; Mode line menus appear incorrectly in some monitor configurations

[Alex]

The menus that display when clicking on various items in the mode line
(major mode, minor mode, buffer position) don't display correctly with
certain monitor setups on X, specifically when using multiple monitors
where the bottoms of the monitors are not even. They appear squished and
are effectively unusable.

FWIW, a similar issue appeared with the mode line tooltips that
displayed when hovering over these items in Emacs 24.5, but they have
since been fixed.

The menu bar menus do not suffer this problem.

When running from the command line, the following message usually
appears:

*** BUG ***
In pixman_region32_init_rect: Invalid rectangle passed
Set a breakpoint on '_pixman_log_error' to debug

I tried to debug this in gdb, but setting the breakpoint made X hang
when encountering this issue, so I was unable to procure a backtrace.

I have attached a picture showing the problem. The static displayed is
the area that I am unable to see, but is included by scrot. The squished
prompt was from clicking on `Lisp Interaction' in the mode line.

popup.png
Description: Squished popup example

In GNU Emacs 25.0.94.1 (x86_64-unknown-linux-gnu, GTK+ Version 3.18.9)
 of 2016-05-17 built on lylat
Windowing system distributor 'Fedora Project', version 11.0.11803000
Configured using:
 'configure --with-gif=no'

Configured features:
XPM JPEG TIFF PNG SOUND DBUS GSETTINGS NOTIFY FREETYPE XFT ZLIB
TOOLKIT_SCROLL_BARS GTK3 X11

Important settings:
  value of $LC_CTYPE: en_CA.utf8
  value of $LANG: en_CA.utf8
  value of $XMODIFIERS: @im=none
  locale-coding-system: utf-8-unix

Major mode: Lisp Interaction

Minor modes in effect:
  tooltip-mode: t
  global-eldoc-mode: t
  electric-indent-mode: t
  mouse-wheel-mode: t
  tool-bar-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  blink-cursor-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  line-number-mode: t
  transient-mark-mode: t

Recent messages:
For information about GNU Emacs and the GNU system, type C-h C-a.
delete-backward-char: Text is read-only [2 times]
Making completion list...
Quit
Making completion list... [2 times]
Quit [4 times]
Type C-x 1 to delete the help window.

Load-path shadows:
None found.

Features:
(shadow sort mail-extr emacsbug message dired format-spec rfc822 mml
mml-sec password-cache epg epg-config gnus-util mm-decode mm-bodies
mm-encode mail-parse rfc2231 mailabbrev gmm-utils mailheader sendmail
rfc2047 rfc2045 ietf-drums mm-util mail-prsvr mail-utils thingatpt
help-fns help-mode easymenu cl-loaddefs pcase cl-lib time-date mule-util
tooltip eldoc electric uniquify ediff-hook vc-hooks lisp-float-type
mwheel x-win term/common-win x-dnd tool-bar dnd fontset image regexp-opt
fringe tabulated-list newcomment elisp-mode lisp-mode prog-mode register
page menu-bar rfn-eshadow timer select scroll-bar mouse jit-lock
font-lock syntax facemenu font-core frame cl-generic cham georgian
utf-8-lang misc-lang vietnamese tibetan thai tai-viet lao korean
japanese eucjp-ms cp51932 hebrew greek romanian slovak czech european
ethiopic indian cyrillic chinese charscript case-table epa-hook
jka-cmpr-hook help simple abbrev minibuffer cl-preloaded nadvice
loaddefs button faces cus-face macroexp files text-properties overlay
sha1 md5 base64 format env code-pages mule custom widget
hashtable-print-readable backquote dbusbind inotify dynamic-setting
system-font-setting font-render-setting move-toolbar gtk x-toolkit x
multi-tty make-network-process emacs)

Memory information:
((conses 16 87251 10741)
 (symbols 48 19665 0)
 (miscs 40 56 172)
 (strings 32 14472 3942)
 (string-bytes 1 414309)
 (vectors 16 11790)
 (vector-slots 8 429244 4485)
 (floats 8 166 98)
 (intervals 56 294 13)
 (buffers 976 13)
 (heap 1024 22194 1031))