Issue when use TextInput inside Window

[panpetedextra]

Hi,

my render function look like this

  render() {
    return (
      <div>
        <Window
          color={this.props.color}
          theme={this.props.theme}
          chrome
          height="300px"
          padding="12px"
        >
          <TitleBar title="My Windows Application" controls/>
          <TextInput
            theme={this.props.theme}
            color={this.props.color}
            background
            label="My Input"
            placeholder="My Input"
            onChange={this.handleChange}
          />
        </Window>
        <TextInput
          theme={this.props.theme}
          color={this.props.color}
          background
          label="My Input"
          placeholder="My Input"
          onChange={this.handleChange}
        />
      </div>
    );
  }

When enter value to both TextInput and swap to another tap (in my case using Chrome just hit F12 for developer tools). The input under Window will change to blank while the input outside Window still has its value.

[gabrielbull]

Please submit a PR and we will accept it.