bug#27816: 26.0.50; X protocol error: BadPixmap (invalid Pixmap parameter) on protocol request 55

[Eli Zaretskii]

> Date: Thu, 03 Aug 2017 19:56:23 +0200
> From: martin rudalics <rudalics@gmx.at>
> CC: bugs@gnu.support, 27816@debbugs.gnu.org
> 
> The doc-string of ‘server-start’ says that this would "Allow this Emacs
> process to be a server for client processes".  How can I "Stop this
> Emacs process to be a server for client processes"?

M-x server-force-delete RET

> Frankly I have no idea what emacsclient is, how it works and how it
> interacts with the server.

See server.el and the emacsclient sources, I think they are pretty
self explanatory, at least as far as the concept goes.