Martin Shaw

Performance issue with the SET_IS_EXPANDED reducer action for Tree component

1

#### Environment - __Package version(s)__: 4.8.0 - __Operating System__: macOS Catalina - __Browser name and version__: Brave 1.42.88 #### Code Sandbox [Link to fork](https://codesandbox.io/s/blueprint-sandbox-forked-74sjtk?file=/src/index.tsx) #### Steps to reproduce 1. Try...