Wont remember window size

I know it's a small problem--if it can even be called that, but every time I open anything on my Mac, anything from Firefox to Finder, I have to manually resize the window to fill the whole screen. When it opens there is a little gap wherever my dock is located. When I had my dock on the left, the gap was on the left, I have my dock on the bottom now, and it does the same thing. I was wondering if anyone else has had this same problem and if they did, if they were able to fix it. Thanks

What OS version do you have? Lion supports full screen, but developers have to catch up.

I am running Lion but even Finder does it too so I don't think it's a problem on Firefox's side. My iTunes used to do that too, but the other day I realized that it doesn't do it anymore...I just don't know how it stopped.

You don't mean that the gap went away, do you? I thought that would always be there.

Yeah the gap between the window and the dock went away so I couldn't see anything except the iTunes window. Is the gap supposed to be there for everything?

Ok this is weird. I'm also having a problem with the keyboard--the lights don't work. I've been trying to fix that too so I tried resetting the SMC. Although that didn't fix the keyboard problem, it did fix this problem. Don't know how that happened but I'm glad that it did.