Hi Samim,
Looking at the code snippet of your Dropdown component I see that in the constructor you are storing *initial* value of props passed to Dropdown to the components state and in the render method you are using `titleCaption` from the state. The state is never updated, so Dropdown always renders the same (initial) value for the title.
Consider using title form the props directly and not storing it in the state.
render(): ReactNode {
const { caption } = this.props;
return (<div className="ui-dropdown__placeholder">
{caption}
</div>);
}
Hope it helps!