[This example](https://codesandbox.io/s/1zn2o513pq) presents a huge performance drop between React 16.2 and React 16.3.

In investigated it and noticed several things:

- Perfomance drop is only visible using development bundle
- This is not related to styled-components (a simple div presents the same problem)
- I tried to investigate in performance tab of Chrome dev tools and I noticed that I get React measures even without "?react_perf"
- React Tree Reconciliation seems very long, do not know why

It is not a big problem for me, but it looks weird, so I decided to [share it on Twitter](https://twitter.com/neoziro/status/979756579296817154),  then @gaearon [invited me to submit an issue about it](https://twitter.com/dan_abramov/status/980036013518139398).


ReactDebugCurrentFiber.setCurrentFiber(nextEffect);
      }
      recordEffect();
      const effectTag = nextEffect.effectTag;
      if (effectTag & ContentReset) {
        commitResetTextContent(nextEffect);
      }
      if (effectTag & Ref) {
        const current = nextEffect.alternate;
        if (current !== null) {
          commitDetachRef(current);
        }
      }
      
      
      
      
      let primaryEffectTag = effectTag & (Placement | Update | Deletion);
      switch (primaryEffectTag) {
        case Placement: {
          commitPlacement(nextEffect);
          
          
          
          
          
          nextEffect.effectTag &= ~Placement;
          break;
        }