message: Checked if noTabChange exists
diff: @@ -22,7 +22,8 @@ class TabBar extends React.Component<any, any> {
  var {selectedTab, onTabChange} = this.props;
  if (this.state.selectedTab !== tab) {
  if (selectedTab == null)
  - this.setState({selectedTab: tab})
  + this.setState({selectedTab: tab});
  + if (!!onTabChange)
  onTabChange(tab);
  }
  }
  