title: React functional component rerenders when props don't change (using useSelector)
body: <p>I'm trying to understand why a change in my <code>component B</code> triggers a re-render of <code>component A</code> and his children.</p>
  <p><code>component A</code> has a <code>useSelector</code> for <code>store.A</code>.<br />
  <code>component B</code> has a <code>useSelector</code> for <code>store.B</code>.<br />
  <code>store A</code> and <code>store B</code> are under the same <code>AppStore</code>.</p>
  <p><code>component A</code> has several children components that are not connected to the store (<code>component A</code> retrieves all the data needed from the store and passes it as <code>props</code>).</p>
  <p>When <code>component B</code> calls an action that modifies <code>store B</code>, <code>useSelector</code> is called in both components.</p>
  <p><em>Here comes the catch:</em><br />
  If I write a <code>useEffect</code> that watches all the data retrieved via <code>useSelector</code> in <code>component A</code>, it never triggers when interacting with <code>component B</code>.</p>
  <p><strong>But it re-renders all the child components all the same.</strong></p>
  <p>I've tried to <code>React.memo</code> a child component of <code>component A</code>, and no change, it always re-renders <code>component A</code> and all his children, even when its props doesn't change (or so is telling me the <code>useEffect</code> watching all the component <code>props</code>).</p>
  <p>Note 1: all components are functional.<br />
  Note 2: if <code>component B</code> only changes its local state and doesn't call any redux actions, <code>component A</code> is never re-rendered.</p>
  <p>I also double checked that all the functions passed as props are using <code>useCallback</code>.</p>
  <p>I really don't understand what is going on.<br />
  I thought that if a component props don't change, they shouldn't re-render.</p>