I took a Toshiba 27" tv back because it had a darker top left corner, and got a Panasonic CT-27D11 instead. No dark corners, but any vertical line near the edge of the screen bows in (or the top and bottom bow out). Is this normal behavior for new TVs? I have seen it years ago on an RCA... The Toshiba had some bowing of vertical lines, but it was VERY minimal. All picture settings are "normalized", i.e. set in the middle.