Tijs Mallaerts <tijs.mallaerts@gmail.com> writes:

> To reproduce:
> - keep the default theme (of emacs -q) or switch to another theme with a dark background (f.ex. deeper-blue)
> - switch to the scratch buffer
> - zoom in to +3
> - hit Return a few times
>
> A slight difference of the background color is visible between the lines on which Return was hit and the blank lines. The first column has
> a different background color as well.
>
> In GNU Emacs 25.1.2 (x86_64-unknown-linux-gnu, GTK+ Version 3.18.9)
>  of 2016-09-17 built on kubuntu
> Windowing system distributor 'The X.Org Foundation', version 11.0.11803000
> System Description:    Ubuntu 16.04.1 LTS

I can't reproduce this on current master.  Are you still seeing this?

If I don't hear back from you within a couple of weeks, I'll just
close this bug as unreproducible.

Best regards,
Stefan Kangas