Radial transparency issue


I experience an issue with radial transparency. I want to make a circle with radial transparency gradient but the "transparent end" is not completely transparent. You can see it in the screenshot with circle and perfectly white rectangle for comparison. The background is white so the circle center should also be white, but it's not! It's light grey, no matter how I manipulate handles or tweak settings.
The linear transparency works fine. White is white.

(Corel DRAW X5)