Tooltips in the pgtk branch behave erratically.

In the tool-bar when you hover an icon the tooltip often blinks
rapidly or does not appear and the button itself goes quickly between
hover/non-hover state. A similar behavior happens with the mode-line.

In the menu-bar they appear behind the menu itself and obscure the
hint in the tooltip.

Attached is a short video which I hope shows what I mean. In case the
attachment does not arrive it is available directly from
http://files.johnmuhl.space/Kooha-2021-04-27-12%3A02%3A38.webm

---

In GNU Emacs 28.0.50 (build 1, x86_64-pc-linux-gnu, GTK+ Version
3.24.29, cairo version 1.17.4)
 of 2021-04-27 built on thelio
Repository revision: 66a36f1e5a323aed3d39db1044a1b71373123832
Repository branch: feature/pgtk
Windowing system distributor 'System Description: Fedora 34
(Workstation Edition)

Configured using:
 'configure --with-pgtk'

Configured features:
ACL CAIRO DBUS FREETYPE GIF GLIB GMP GNUTLS GPM GSETTINGS HARFBUZZ
JPEG
JSON LCMS2 LIBOTF LIBSELINUX LIBSYSTEMD LIBXML2 MODULES NOTIFY INOTIFY
PDUMPER PGTK PNG RSVG SECCOMP SOUND THREADS TIFF TOOLKIT_SCROLL_BARS
XIM
GTK3 ZLIB

Important settings:
  value of $LANG: en_US.UTF-8
  value of $XMODIFIERS: @im=ibus
  locale-coding-system: utf-8-unix

Major mode: Lisp Interaction

Minor modes in effect:
  tooltip-mode: t
  global-eldoc-mode: t
  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

Load-path shadows:
None found.

Features:
(shadow sort mail-extr emacsbug message rmc puny dired dired-loaddefs
rfc822 mml mml-sec epa derived epg epg-config gnus-util rmail
rmail-loaddefs auth-source cl-seq eieio eieio-core cl-macs
eieio-loaddefs password-cache json map text-property-search seq byte-
opt
gv bytecomp byte-compile cconv mm-decode mm-bodies mm-encode mail-
parse
rfc2231 mailabbrev gmm-utils mailheader sendmail rfc2047 rfc2045
ietf-drums mm-util mail-prsvr mail-utils time-date subr-x cl-loaddefs
cl-lib iso-transl tooltip eldoc electric uniquify ediff-hook vc-hooks
lisp-float-type mwheel term/pgtk-win pgtk-win term/common-win tool-bar
dnd fontset image regexp-opt fringe tabulated-list replace newcomment
text-mode elisp-mode lisp-mode prog-mode register page tab-bar menu-
bar
rfn-eshadow isearch easymenu timer select scroll-bar mouse jit-lock
font-lock syntax font-core term/tty-colors frame minibuffer 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 composite charscript
charprop
case-table epa-hook jka-cmpr-hook help simple abbrev obarray
cl-preloaded nadvice button loaddefs faces cus-face macroexp files
window text-properties overlay sha1 md5 base64 format env code-pages
mule custom widget hashtable-print-readable backquote threads dbusbind
inotify dynamic-setting system-font-setting font-render-setting cairo
move-toolbar gtk x-toolkit pgtk lcms2 multi-tty make-network-process
emacs)

Memory information:
((conses 16 51314 11250)
 (symbols 48 6592 1)
 (strings 32 18173 1512)
 (string-bytes 1 598869)
 (vectors 16 13361)
 (vector-slots 8 177963 9848)
 (floats 8 22 61)
 (intervals 56 195 0)
 (buffers 992 10))