Every yellow flash is a re-render. Interact with the demo, spot what shouldn't be flashing, then open the solution tab to see the fix.
Exercise 1 of 1
Pass expensive components as children to isolate them from state changes in the wrapper.
IntervalSection renders: 1
ExpensiveStats renders: 1
This component does not use interval — but it still re-renders.
Click an interval button. ExpensiveStats flashes every time even though it doesn't use interval — it re-renders because its parent re-renders.