Extjs windows out of browser

下面是代码

 

Ext.override(Ext.window.Window, {
    listeners: {
        move: function(in_this, x, y){
            var maxX = Ext.getBody().getViewSize().width-20;
            var maxY = Ext.getBody().getViewSize().height-20;
            x = parseInt(x);
            y = parseInt(y);
            if(x<0 || x>maxX || y<0 || y>maxY) {
                if(y < 0)
                    y = 0;
                if(x < 0)
                    x = 0;
                if(y > maxY)
                    y = maxY - in_this.getHeight();
                if(x > maxX)
                    x = maxX - in_this.getWidth();
                in_this.setPosition(x, y);
            }
        }
    }
});