bug#27357: 26.0.50; Emacs starts fullscreen in Ubuntu 17.04

[Lars Ingebrigtsen <larsi@gnus.org>]

martin rudalics <rudalics@gmx.at> writes:

>> I just noticed something amusing: If I put the mouse over the mode line
>> things that pop up tooltips, they're all displayed approximately 2x from
>> the position they're supposed to:
>>
>> https://youtu.be/oWjmL-8leVo
>>
>> This is with the current git Emacs, with -Q on Ubuntu 17.04 (with a
>> HiDPI display).
>
> See bug#18429, bug#20619, bug#21348, bug#21469 ...

Oh, wow, so this has been a known problem, apparently related to gtk3
with HiDPI, for almost a couple of years, but nobody has been able to
track down just exactly where Emacs is doubling the sizes?

I spent a few hours on this a few days ago, but I was unable to follow
the call chain logic (which is somewhat asynchronous).  And some of the
effects seem to be timing related, somehow...

I've read through the emails in question, but the patch posted didn't
seem very promising since it only handled tooltip placement and not
window sizing...

Do you have any ideas for where I should be poking around to see where
these bogus doubled values come from?

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no