I am having a strange problem and I'm not sure whether it is usual or not with glass trackpads. When I use the trackpad with my hand resting on the area outside the trackpad the trackpad works fine. However, when I use the trackpad without my hand touching anywhere else on the machine (so my only contact with the machine is just my finger on the trackpad) the cursor seems to jump around erratically. It's not a huge problem because most of the time I am resting my hand/s on the machine while I am using it but it would be nice to know if this is not quite right. Thanks.