I am using the Microsoft Ergonomic wireless deskset 7000 and have recently run into a problem. I am using a iMac 24 with an external 22" LCD as my second monitor. If I am on the iMac screen and using an application the mouse might for no apparent reason jump to the secondary screen. I can't figure out what is causing this. I have checked every setting in the mouse and keyboard settings but still have the problem. I even went into the OSX mouse and keyboard settings and moved all the sliders to the left or minimum setting. Still this loss of focus happens. If anyone has any ideas please let me know.