title: Is that possible that a component will also be re-rendered without props and states changing
body: <p>In React, if father component "A" re-rendered and change the position of its son component "B", but B's props and states aren't changed, then will the "B" be re-rendered? If it will, why is that necessary?</p>
  
  <p><a href="https://i.stack.imgur.com/1nEM9.png" rel="nofollow noreferrer">Below is code in parent component, and "Poker" is the child. "this.props.localPokers" is an array which can be added element by clicking a button:</a></p>
  
  <p><a href="https://i.stack.imgur.com/WXucA.png" rel="nofollow noreferrer"></a></p>
  
  <p><a href="https://i.stack.imgur.com/KW7JB.png" rel="nofollow noreferrer">the position of bottom poker has changed</a></p>
  
  <p><a href="https://i.stack.imgur.com/b52gY.png" rel="nofollow noreferrer">Well, I insert console.log in child render(), it does re-rendered the DOM, so I think the question now becomes if the updating of the child is necessary?</a></p>