Why status bar show again when my app resume - On Android

Hi friends,

I'm learning Titanium, I have a trouble with it: I open a window with properties :

var win = Ti.UI.createWindow({
        height : height,
        width : width,
        navBarHidden : true,
        fullscreen : true,
        top : 0,
        left : 0,
        orientationModes : [Titanium.UI.LANDSCAPE_LEFT],
        //backgroundImage : '/images/dangnhap.jpg'
    });

and tiapp.xml

<statusbar-hidden>true</statusbar-hidden>
 <fullscreen>true</fullscreen>
 <navbar-hidden>true</navbar-hidden>

My app open perfectly and status bar is hide, but when i press home button ( hard button ) to exit homescreen and resume it, status bar show again, i can't hide it, please tell me why and give me a good solution.

Thanks so much!