The new Taskbar in Windows 8 finally spans multiple monitors, and can be customized so that the taskbar buttons on each monitor are the buttons for windows open on that monitor. You can also make both taskbars show all windows if you choose.
To access the new settings, head into Taskbar Properties by right-clicking on the Taskbar and choosing Properties. Once there, you’ll see the “Multiple displays” section at the bottom of the dialog, where you can quickly check the box to enable or disable showing the taskbar across displays.[howtogeek.com]