When you lock your nokia n8 and when you click the menu button do check your watch
it is half purple half black.. then its a AMOLED glitch you need to change your nokia n8 !

Nokia N8 costs around $560 in India and it takes Nokia about $187 to make. The Nokia N8 hardware were supplied by Samsung Electronics Co., Toshiba Corp. and Texas Instruments Inc.  California-based iSuppli have torn down the Nokia N8 and he revealed the specs of N8 hardware.

The most expensive element of the N8 is the display and touchscreen, which cost $39.25. The chipset used to run the operating system and applications in the N8 cost $22.It includes digital and analog processors made by Texas Instruments and a Broadcom Corp. multimedia processor with support for the HDMI port for high- definition TV output. Memory components, including 16 gigabytes of mass storage, cost $37.12. The cost of the camera elements added $31.08.

iSupply has performed a teardown of Nokia's N8, and they say that the most expensive part is the display which costs $39.25. This includes the 3.5" AMOLED and the touch overlay. The whole phone costs $187.47 to build (and it costs $549 to buy unlocked...). The AMOLED is made by Samsung of course, while the touch layer is made by Synaptics.