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I don't know if you've ever experienced such a behavior from your mouse pointer but it's happened to me several times.
The thing is, when I buy a brand new mouse, everything is fine for some time (a year or two) but after that, the mouse pointer starts twitching sometimes.
I first thought it's because of those old ball mice and due to their mechanical nature that this happens. But it keeps happening to the optical mouses too. I wonder what might cause this problem and how to avoid it?
This happens when the mouse is idle. I mean I'm not touching it at all and I use a standard mouse pad.