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

[Alex]

Alex <agrambot@gmail.com> writes:

> I coincidentally stumbled across an easy recipe for this bug (or at
> least a similar bug):
>
> M-: (setq display-line-numbers t)
> M-: (setq mouse-drag-and-drop-region t)
>
> Then select a region, click on it (mouse-1), and drag the mouse. The
> line numbers will disappear until you release the mouse.
>
> Hopefully you can reproduce this on your end this time, Eli. To be
> clear, this is with a GTK build.

Sorry, I should have also mentioned that this is indeed only the case
when x-gtk-use-system-tooltips is non-nil.