It's just same with Windows 7 Task Bar!
You can multitasking and task-kill everywhere, anytime.
Tab the start button to show/hide the task bar and Long press it to show/hide the start menu.

In some versions of MIUI, you are supposed to check 'Show popup window' in application setting

Required Android O/S : 3.0+

Screenshots Windows 7 Task Bar








Download Windows 7 Task Bar