Has any software been recently “upgraded”? Sounds like a browser issue, but I know just enough to be dangerous. You could try a system restore to before you noticed it and see if it goes away. More likely a software issue of some kind IMO.
I DID have one of those "36,000 updates, do not turn off computer" at a start-up about two or three months ago.
I honestly don't know when this color thing happened, but I've known about it for some time ... 6 mo to a year.
Never bothered me before, but I had occasion to talk to my bank the other day and I was with their IT guy for 15 or 20 minutes looking at the situation and it was determined it is with me and not with them.