On Tue, Oct 22, 2019 at 3:52 PM Ingo Lohmar <ingo.lohmar@posteo.net> wrote:
I am writing to the org-mode list first, because I have only been able
to reproduce this problem in org-mode.

With a recent Emacs master build, faces can have the :extend t property
to indicated that they should extend after the newline.  This is useful
for a user to customize, eg, for `org-block', and it also applies to
default faces like `region', `highlight' or `secondary-selection'.

Hello,

I have been seeing this issue too, but I haven't found time to create a proper bug report for it.

But now that you have this email, I am forwarding this to the Emacs devel list too.

The issue occurs because of the new :extend feature for faces to extend till end of lines.

With that enabled, I have also seen that the cursor "hides" automatically only at end of lines inside the Org source blocks. i.e within

#+begin_src emacs-lisp
(message "hello")X
#+end_src

Above: X is where the cursor would be, but it would not be visible (with the :extend t added to the org-block face). The cursor would show up again on doing C-b i.e. bringing it to any column position other than the EOL.
 
Using this with a current elpa pkg of org-mode, and setting :extend t on
faces like `org-block`, "often" the cursor vanishes at the EOL of a line
using such a face.  It reliably happens for `org-block', only sometimes
for `secondary-selection'.

Has anybody else experienced that as well, or do you have any pointers
on how to further investigate this?  I think I remember that org-mode does
something with text overlays, but I can't relate that to what I see.

There might also be an issue with face inheritance and the new :extend
attribute --- I might post on emacs-devel to get a better idea of that
as well.

Thanks,
Ingo