Hi all, I got my MBP a week ago and so far I love her. One thing I notice however is that the arrow keys seem to stick up higher than other keys on the board. Looking at them up close it appears that the small plastic piece that is on the bottom of all keys is dislodged on the left side of these keys, plus I seem a small loop shaped thing when looking under these keys. Is this normal? I realize it i might be cosmetic but I am concerned that lots of dirt might get under the keyboard.
Well they are "scissor" keys which by design form a sort of X. There is the key itself [flat] snapped onto the top of the X while the bottom of the X is snapped onto the keyboard. They are kept erect by a little rubber piece in the middle which normally is stationary and can't be removed. In earlier models the rubber peice was removable and as a result a complete pain in the ass.
You can pry 'em off with an object such as a pocket knife though if you don't know what your doing you could permanently damage the scissor part. But basically, if the bottom of the X is snapped correctly into place, the key itself could be snapped in just by applying
slightly more pressure than normal.
If you popped one off, once you figure out the proper way to place it back in, attach the scissor part to the keyboard first and then snap the actual key on afterwards.
This image shows
one half of the scissor part but you can see the "loop" of the piece and how it snaps in.
Otherwise, the loop you may be seeing could just be the area around the rubber piece where it is attached to the keyboard. Dirt and crumbs could pose physical problems while pressing a key, but otherwise it is, for the most part, completely enclosed preventing those larger crumbs from getting inside the machine itself. The same is not to be said for liquids and dust.