I have a Magic Mouse that's a few years old (I think I purchased it in the Marketplace from someone that had a few from iMacs). This isn't the latest rechargeable one. Whenever it's bumped up against my keyboard, or if I pick it up and don't put it down ever so gently, it'll disconnect from my Mac. Is this a known issue that's hopefully easy to fix or should I replace it? The batteries seem pretty tight so I don't think that's the issue. It's also done this through another set of batteries, so that's not it either. If I do need to replace, should I throw this away or is there a market for bad Magic Mice?