This problem is caused by the conflicts between start11 and displayfusion.
displayfusion will make some effect to the taskbar,although i just tick every settings off.
I just download the newest iso file in microsoft official website then just double click at the setup.
First time,i install start11 and displayfusion.Problem still exists.
Second time,i am afraid to install displayfusion so i have not installed it yet.Now everything works fine.
I also paste a topic in their discussions.But if this situation is not solved.I am afaid i will have to waste my money in displayfusion..