horizontal layout and percentage width do not work well

titanium sdk: 2.1.1 os: mac os platfrom: iphone simulator 5.1

when the table row has a horizontal layout and the child view in it has a percentage width, the child view is not shown, take a look of the following code, button is presented, but the leftview is not:

var row = Ti.UI.createTableViewRow({
                    top:5,
                    bottom:5,
                    height : 60,
                    width: Ti.UI.FILL,
                    layout : 'horizontal',
                    selectionStyle: 'none'
                });
var leftView = Ti.UI.createView({
                    left : 0,
                    width : '75%',
                    height : 50,
                    layout : 'horizontal',
                    backgroundColor:'red'
})
var button = Ti.UI.createButton({
                    title : 'Button',
                    left : 0,
                    //top : '20%',
                    height : 30,
                    backgroundColor : '#104E8B',
                    color : '#FFFFF0',
                    font : {
                        fontSize : 14
                    },
                    style: Ti.UI.iPhone.SystemButtonStyle.PLAIN
});
 
row.add(leftView);
row.add(button);
tableView.appendRow(row);