I noticed the appearance of a linear smudge or streak on my DX last week seemingly out of nowhere - about 3 cm vertical x 0.5 cm towards the left side of the central part of the screen - clearly between the front glass layer and something below it. It looked like water damage but the phone never got wet - perhaps parts of the LCD screen became separated? I dropped the phone once but did not notice this after this event. This would cause some trouble in using the touchscreen occasionally whereby things I selected would highlight the "smudge" but not where I was pressing. I now believe this to be related to my extended battery - if you are curious, please read below for what happened to me. I took the phone to a VZ store and the tech examined it a while, confirmed there was no water damage and ordered me a replacement (which he said would be a new DX since they don't yet have any refurbs). The new replacement arrived and I put in the extended battery, fired it up and restored my apps. As soon as I fired it up I noticed a similar but slightly smaller screen smudge with identical characteristics to my original phone. After swapping batteries between the phones (native 5x and extended 6x) and exchanging battery doors (tight fitting 5x and normally fitting 6x) I was able to reproduce the smudge on both phones ONLY while the extended battery was installed, sometimes after 30 minutes or so of using the phone, but inevitably it would appear on whichever phone had the extended battery - regardless of which battery door was used. Both phones appeared normal with the regular battery every time it was inserted. I'm going to go back to VZ and show them the two phones and have them exchange the extended battery (purchased from them) and see if I have a defective battery or whether I have two unlucky phones or perhaps this is a bigger problem?? Anybody else have any thoughts or have a similar experience?