I can compile Emacs 26.1 RC1 ok, and use it locally on the host fine.

However, when attempting to ssh -X to host via PuTTY 0.70 and launch the Emacs gui, emacs is not displaying correctly. See screenshot below.   Using Windows xserver program VcXsrv (1.19.6.3).

[![Emacs 26.1 RC1 GTK3 display issue][1]][1]

I suspect this issue is related to some combination of GTK and Xming/VcXsrv, however the behavior does change between Emacs 25.3 and 26.1 RC1, see table below:

    | emacs    | x-toolkit | result
    +----------+-----------+-------
    | 26.1 RC1 | gtk3      | bad
    | 26.1 RC1 | gtk2      | bad
    | 26.1 RC1 | motif     | ok
    | 25.3     | gtk3      | ok
    | 25.3     | gtk2      | ok

 - `emacs -Q` produces the same result.
 - freshly compiled on Opensuse Leap 43.2 and CentOS 7 produces same result
 - `XLIB_SKIP_ARGB_VISUALS=1 emacs` same result 
   - References: [Link1], [Link2]



./configure options I ultimately desire:

`--with-x-toolkit=gtk3 --with-xwidgets  --with-modules --with-mailutils`

Where gtk3 is required for xwidgets, so motif or other x-tookkits are not the best solution.

Note: with Xming 6.9.0.31  (not vcxsrv)
I get core dumps with error messages referencing this GTK bug:
https://bugzilla.gnome.org/show_bug.cgi?id=85715

Can anyone else replicate this problem or have any ideas how to resolve?

    wget ftp://alpha.gnu.org/gnu/emacs/pretest/emacs-26.1-rc1.tar.xz
    tar -xvf emacs-26.1-rc1.tar.xz
    cd emacs-26.1
    ./configure --with-x-toolkit=gtk3 --with-xwidgets --with-modules --with-mailutils --prefix=/home/test/emacs_26.1_gtk3
    make && make install 
    # launch emacs, confirm ok
    # login to windows, launch ssh -X putty session to linux host, + vcxsrv/xming
    # launch emacs - compare to screenshot

Thanks!


  [1]: https://i.sstatic.net/2oplc.png

[Link1]: https://bugs.launchpad.net/elementaryos/+bug/1355274
[Link2]: https://emacs.stackexchange.com/questions/40990/emacs-aborted-core-dumped-centos-7-0-emacs-25-3-please-help