properties window is not showing property with Browsable attribute

Plz Check the code snippet,

 public class MyCompositeControl:CompositeControl
    {
        [Browsable(true)]
        [Category("Appearance")]
        public string FirstText
        {

I am creating one custom control and for a public property FirstText i have added the  Browsable attribute.

But  still the FirstText peroperty is not showing in the properties window when i right click the control in the design view.

Note: If you check the HTML then the property FirstText is available.If you add [Browsable(false)] attribute to the public property, even then the attribute is available in the HTML.

Why so happening?