Why taskbar stays ? Diablo 3

I have this issue only when i launch D3 with isboxer the image holds the taskbar down below and i can't figure it out how not too show it.

Here is a pic to have an ideea http://i.imgur.com/EANTSzb.jpg

Please hepl me out i want full screen on 1st monitor

[MiRai]

You either need to go into the region editor of your Window Layout and set Region 1 to be always on top when a game is in foreground, or you need to auto-hide the Windows task bar.