We purge it [here](https://github.com/facebook/react/blob/b11540ccb2321aeb7259fcf0b3a38aeeea35231d/src/isomorphic/ReactDebugTool.js#L88-L89) but this code doesn’t run because of the [early exit](https://github.com/facebook/react/blob/b11540ccb2321aeb7259fcf0b3a38aeeea35231d/src/isomorphic/ReactDebugTool.js#L53-L57).

Need to fix this and add a test case to make sure we don’t regress on it.

var item = tree[id];
  if (item) {
    var {childIDs} = item;
    delete tree[id];
    childIDs.forEach(purgeDeep);
  }
}
var ReactComponentTreeDevtool = {
  onSetDisplayName(id, displayName) {
    updateTree(id, item => item.displayName = displayName);
  },
  onSetChildren(id, nextChildIDs) {
    updateTree(id, item => {
      var prevChildIDs = item.childIDs;
      item.childIDs = nextChildIDs;
      nextChildIDs.forEach(nextChildID => {
        var nextChild = tree[nextChildID];