Just noticed this now -- whenever I tap the trackpad (very lightly, without clicking) I hear a high pitched "thik" on the left side. The right side of the mouse button doesn't thik or anything. Sounds like the mouse button is loose but I've tried pushing harder to jar it back in place but it doesn't work. In fact, if I click the mouse using the left side of the button I hear 2 clicks -- that light thik then the button click. Is this a common problem?