Probably a mac problem, or an osso problem

Once in a while, when I am moving my cursor to the top of the screen, I hear a whoosh, and it turns out I have totally negated one of my categories in my whatsit line, for example, all my news sources, by mistake. I forget what you call that, but in my case, the line includes a2k, yahoo baseball, sport, google, google image, gmail, news, yahoo, youtube, blgs, flgs, ref, trv, and much more.

I assume this has something to do with safari, that I can just eliminate something on my browser with a effort to put my cursor to the top of the screen for some reason, to cause a whoosh.

Is this common? I'm getting irritated. This is the second time today, thus I'm very irritated.