When scrolling down on presets, "Overworld" icon would change it's background once scrolling all the way down to a brownish color. It's not a big deal, but I cannot reproduce this in any other version.

Scrolling down, the icon's background should remain the same grey background.

After scrolling down fully, it changes the icon 'Overworld' color to the same brownish color as the object in the icon.

Steps to Reproduce:
open in 854x480 resolution (Important)
Single player
new world,
more world options: Super flat
and customize..
Presets
scroll all the way down, and notice the
overworld icon should have changed..

This doesn't happen in fullscreen, must be in large or normal GUI Scale.
Tested with last version of snapshot and 1.6.4; glitch nonexistent as it seems.