Hi, I have a macbook pro that I purchased in 2011. It is working perfectly fine and I don't really have any problems with it (so far). However, today I noticed that when I look really closely at the black bar that connects the screen to the keyboard, from atop I can see parts of what's underlying. It's hard for me to put into words what I can see, but what I can see looks like edges, and I'm not exactly sure what this is. Is this normal?