Icon Scale, use 40x40 icons in real 1:1 scale, UI problem

[beb]

I assure you, I've explored every avenue; even at 514x514, the effect appears distorted.

Let me clarify, the icon file is flawlessly designed at 42x42, in line with all other icons:
Image: https://www.dropbox.com/s/fph2i4gc3jik99u/KFC.png?dl=0

So, I was wrong in that part. My bad.

By the way, just noticed, -- why do you draw your icon as 42 x 42 24 bpp (RGB), and not as RGB/A . Maybe this is the key to your issue?

[Sob]

About KFC icon, my icon editor shows those supposedly black parts as transparent. And so does everything else I tried, so it explains why on your white button bar you see white.