Malcolm, Doug,
Thanks for the replies.
The Color Editor issue doesn't seem to be re-occurring after the re-install, only the disappearing RGB readouts.
I have already raised a formal ticket with Phaseone support. I received a reply asking for a "recording". In truth, I didn't even know what that was. I since discovered that I would have to install a piece of software and record the actions of the fault.
a. I hate installing anything unnecessary on any of my computers.
b. It would probably cost me.
c. The fault is about as straightforward as could be in terms of its repeatability (it may be incredibly complicated "under the hood", so to speak, but that's their problem) - you can either see the RGB readouts disappearing after using the Spot Removal tool, or you can't, period.
After I wrote back and said I couldn't provide a recording, I heard nothing more from them. That's a four days ago, I think.
Let me be clear, this is the best processing software I have ever used - when it works.
I live in hope.
Thanks again.
D.