Re: master 1555453694: Implement `alpha-background' on non-Cairo builds

[Po Lu]

Jose A Ortega Ruiz <jao@gnu.org> writes:

> i forgot to add that, when built with no-toolkit and without any alpha
> or alpha-background spec, there's another new problem with exwm.  exwm
> has a "system tray" where it puts applets like nm-applet.  before the
> last changes to support alpha-background in non-gtk builds, exwm's
> system tray had been working for me flawlessly.  now it doesn't work at
> all (the icons don't show up in the tray area, and new, empty buffers
> are created instead).  

EXWM probably doesn't know about 32-bit visuals.  I suspect it's
creating a window to hold the system tray with depth and visual set to
CopyFromParent, but not creating true-color pixels correctly.

You can work around the problem by adding:

  Emacs.visualClass: TrueColor-24

To your X defaults file, but that will also prevent `alpha-background'
from working.

Thanks.