I have a Macbook and when I hook it up to a 26 in. TV with the VGA cable (I bought the adapter) it will show the wallpaper, but not the dock, or the bar across the top of the computer. It also wont show the mouse movement. It works fine with the Toshiba PC. Is there something I need to do to the Mac. I am a little new to the Macs. Help. Thanks.