I have owned my 27" Apple Cinema Display since new in late 2010 and it has just suddenly (today) developed a linear shadow in the top right corner and all down the right side. I do not believe this is the "fine dust under the screen" issue that has plagued iMacs due to their fans drawing in dust or smoke as it has appeared suddenly and is more noticeable when the monitor is waking from sleep. After a prolonged warm up the shadow is a little less noticeable. I also don't think it is the same as the "loose gasket in the LCD screen drifting into view" which can occur in all ACDs and results in what looks like a foreign object in a hard band at the very screen edge. That can be resolved by removing the LCD panel and disassembling it to reposition the gasket. My issue is a slight darkening in the top right a short distance down and in from the top right corner with a firm inner edge and diffuse outer edge that continues down the entire right side of the screen to the lower corner. It feels to me like a backlight or backlight driver issue. Here is an iPhone pic of the top right corner, desaturated to show just the brightness difference. Ignore the diagonals in the left side of the image as they were from my wallpaper. The moire patterns are simply from resizing the image in GIMP. In this image I have used the brush tool to emphasize the inner and outer edges of the shadow... Now I am well out of AppleCare (3 years beginning late 2010) so I suspect this is not an economical repair as they would probably quote for a whole new panel. Opinions?