It's a problem with every plasma TV ever made. I've got one of the last Panasonic Viera's which, after almost 10 years, has a slight dark patch around the place

It's a problem with every plasma TV ever made. I've got one of the last Panasonic Viera's which, after almost 10 years, has a slight dark patch around the place where subtitles tend to appear (I'm from the Netherlands where almost all non-dutch content is subtitled) It's only really noticeable when looking at a uniform gray screen which is not my content of choice, but it's there.