This is a cosmetic problem, but I find it annoying.
When I scroll the Registry Cleaner display in CCleaner, it's corrupted by horizontal gray lines, as shown in the attachment. It happens when I scroll down by clicking on the vertical scroll bar or on the down arrow, but not when I drag the scroll bar. When I scroll up, the horizontal gray lines separating entries disappear. Obviously, there have to be enough entries in the display area to see it (or the window length can be reduced). This happens with versions 3.20 and 3.14, and if I recall correctly, for several versions before those. I'm running Windows XP SP3.