bug#40375: 27.0.50; yank unexpectedly depends on progn

[Eli Zaretskii]

> From: Markus Triska <triska@metalevel.at>
> Date: Mon, 13 Apr 2020 20:01:13 +0200
> Cc: 40375@debbugs.gnu.org, Noam Postavsky <npostavs@gmail.com>
> 
> Once this issue occurs, what is yanked is no longer predictable for me:
> Sometimes it is text that is selected in other applications, sometimes
> it is text that was copied to the clipboard from other applications, but
> is no longer selected. It feels like there is no clear pattern.

Do you have some clipboard-managing software installed and active?  If
so, can you disable it?

> What I would prefer in all these cases is that Emacs yank the text that
> was most recently killed in this example, which is the sample image that
> you can reproduce.

When the system clipboard holds stuff from another application, C-y
will by default yank that first.  If some software on your system
rearranges the clipboard in some way that makes Emacs think the stuff
in the clipboard was copied there after you killed something in Emacs,
Emacs will behave as you describe.

IOW, I don't believe this is an Emacs problem.