Hello, I'm currently going through a phase of mice.. i have one wired mouse (Logitech MX510) which has excellent tracking and excellent response the x and y axis movement is almost perfect, *BUT* i really need a bluetooth mouse as i'm on the road alot and the less wires the better! Plus I really dont want to have a dongle I have to cart around everywhere. So..... I bought a Wireless Might Mouse mini.. Then a Logitech V270... Then a *shudders* microsoft wireless laser 8000.... and they all have the same tracking issues! It's not the response time, all of them are great and 95% of the time you dont notice the lag.. but they all suffer from the same issue which is the vertical movement in proportion to the horizontal movement of hte mouse cursor on the screen is no where near the same as with my wired mouse! If you're head just exploded... please read on! Basically, with my wired mouse, when I moved the cursor up/down vs left/right the tracking was pretty nice, there were no great movements of the mouse to move the cursor up/down and moving the cursor left/right felt about the same. However.. with all of the bluetooth mice I have here I'm finding that there is quite alot of wrist/arm movement to move the cursor up or down in proportion to moving left or right. When I move the cursor left or right I'm finding that the slightest physical movement is moving the cursor great distances but moving it up or down requires alot of effort. At first I thought that it was the non-apple mice that were casuing the problem, so I bought a Mighty Mouse but thats giving me the same movement issues! I've tried playing around with the cursor speeds but to no avail.. it gets *fairly close* to being normal but still uncanny to use and then its just way to sensitive. Does anyone else have this issue? Is there an app or some way I can define the x/y tracking behaviour of my mice? Or am I just going bananas!??! Thanks!