monitor with screwed colour in bottom-right of screen

posted to sci.electronics.repair, but some of you guys might be able to help too... I've just been given a nice Iiyama 21" screen for free which seems to run quite happily, with the exception that the colours are screwed in the bottom-right inch or so of the display; the same sort of effect that would be achieved by holding a big magnet in that corner of the screen. Degaussing seems to have variable effect; sometimes it almost cures it and sometimes it just makes it worse, but it never goes away. Any ideas what might be up with it? Or is it a mechanical fault (i.e. the picture tube just shot)? Also, is this something that will get worse now it's started? If not, I could almost live with replacing the 17" screen on my desktop PC with this one, as the 17" is getting a little fuzzy and at least this 21" screen has a crisp display even if there is a bit of colour damage right in the corner... cheers Jules