some comments

packages/client/src/render/attachChildren.js

@@ -99,6 +99,7 @@ const areTreeNodesEqual = (children1, children2) => {
 
   let isEqual = false
   for (let i = 0; i < children1.length; i++) {
+    // same context and same children, then nothing has changed
     isEqual =
       deepEqual(children1[i].context, children2[i].context) &&
       areTreeNodesEqual(children1[i].children, children2[i].children)

packages/client/src/render/prepareRenderComponent.js

@@ -79,6 +79,7 @@ export const createTreeNode = () => ({
     const node = this
     return () => {
       if (node.children) {
+        // destroy children first - from leaf nodes up
         for (let child of node.children) {
           child.destroy()
         }