VFB why reseting one of color curve point doesn't reset img

[Paul Oblomov]

Well seems like a bug
Simple image. VRay VFB used. Use colors curve correction is checked. So I'm adjusting colors by moving tangents or points - see how it's interactively changes at VFB - BUt when I tries to reset tangents - VFB doesn't resets CORRECTLY (I mean it refresh itself only if any window is over it).