Huh, I had a line just like this one (but almost at the top of the screen) - but while on vacation in Spain it went away! It has been gone for about two months now...
I have absolutely no idea how this happened, but where I normally live it is *never* above 20 degrees and not much sun ever hits the screen. In Spain, we had about 30 degrees (celsius, obviously
), and I read books by the pool - it occasionally got pretty hot, but I generally tried to keep it at an angle to limit the effect a bit. It was also heavily in use - probably did about a couple of hundred page flips pr day.
I have no idea if this is a fix, or if it will return, or what. I would also not really recommend any to do as I did, as according to the literature that kind of use could *damage* the display. Well, I beg to differ. </famous last words>. At the moment, it is at least working better than it has for about a year (it's about a year and a half old), and I'm quite happy with it again!
/R