menubar not updated/refreshed correctly when switching buffers

[David Girault]

Step to reproduce:

- Launch a clean session of emacs25-x from command line:
  user@machine:~$ emacs25-x -q --no-desktop
- Clic on menubar. Check drop down menu are ok.

- Switch to *scratch* buffer using menubar.
- Now clic 'List-Interaction' menu in menubar. It is empty!!!

- Open menubar by press F10 on keyboard
- The following warning apears on console
(emacs:8238): Gtk-WARNING **: no trigger event for menu popup
(emacs:8238): Gtk-WARNING **: no trigger event for menu popup
- With keyboard, go right up to 'Lisp-Interaction' menu. It is full featured!
- Exit menubar, then clic again on 'Lisp-Interaction' menu. It is still ok.

- Switch back to 'GNU Emacs' using 'Buffers' menu
- Try to switch back to '*scratch*' using 'Buffers' menu -> It don't work.
- Refresh menubar with F10, previous line should work

and so on...

There is a big problem with menubar refresh using mouse.

[David Girault (dfgweb)]

In case this is related, I use the following dual monitor setup:

xrandr --output eDP-1 --auto --scale 1.0x1.0 --pos 768x2304 --primary --output DP-1 --scale 1.6x1.6 --pos 0x0 --fb 4096x3904

Also have tooltips very badly positionned...

[David Girault (dfgweb)]

Well, after playing with hidpi setting, it appears that ALL bugs (empty menu, badly positionned tooltips) are only when windows scalling is set to 2!