Hacks and duplicates not showing properly

[help_anna_me]

I have a weird problem, I hope I can explain it properly.

There are hacks and duplicates present in my download folder but none of them are showing as red/pink in Clean Installer, until I change to a different window (eg from CI to Firefox), then go back to CI, the red will show on the area of CI that was covered on the screen by the other window, until I scroll up or down or click something and the red disappears.
It used to work fine until recently, but as far as I can tell nothing has changed on my pc. I have installed the latest version but that hasn't fixed it.

Help?

[Mootilda]

I have no idea. At least you have a workaround.

[Update:]

It's possible that your machine is running out of windows resources. Try minimizing everything else, so that the Clean Installer is the only active window.

If that doesn't resolve it, try rebooting your computer: a full reboot (not suspend or hibernate).

[help_anna_me]

Thank you for replying. Still can't get it to work properly, but like you say at least I can get around it (slowly!)