Subject: Re: bug#27647: 26.0.50; Line numbers implemented natively disappear momentarily when frame out of focus

From: Eli Zaretskii <[email-masked]>
Date: Tue, 11 Jul 2017 17:31:01 +0300

> From: Kaushal Modi <[email-masked]>
> Date: Tue, 11 Jul 2017 03:43:07 +0000
> Cc: [email-masked]
> 
>  When you say "line numbers disappeared", do you mean as if you set
>  display-line-numbers to nil, i.e. the text starts at the left edge of
>  the window? 
> 
> Yes. Exactly. And they reappear automatically too once that window is in focus again. 

In that case, I suspect that some of your customizations somehow
temporarily reset display-line-numbers to nil.  You could try to use
Lisp watchpoints (see "Watching Variables" in the ELisp manual) for a
single buffer where this happens, to find out which code does that.

Alternatively, instrument your functions that reset
display-line-numbers to log messages to some buffer with useful
information, such as the Lisp backtrace, and when the problem happens,
examine the log for clues.