Transparency: Not really a bug, but a curious observation

[gyanantaran]

So, I was trying to reduce the opeacity, but maybe the blurring makes the opacity discrete (non-continous). Anyways, I ended with the following effect:

Here you can see that I have window.opacity = 0.0019607843132689597, and the screen is completely transparent, but when I increase window.opacity by 0.0000000000000000001, the screen goes completely opaque

I am just curious why that is the case. How did I get that number? I did a manual binary search!

Thanks

edit1: updated compressed screenshots

[gyanantaran]

"..goes completely opaque", I meant, drastically opaque.

[chrisduerr]

Just floating point stuff, not much of a surprise really.

[kchibisov]

Could be in the driver itself, because on e.g. my GPUs this value works fine.