Tree renders child incorrectly when parent to an only child gets updated then the child gets updated

[justindoherty]

This is sort of a spin off of #353 that I am able to reproduce in 0.3.5 and the latest master d238a52.

If I update a parent to an only child then update that child I get a "row is undefined" error in the console and the child row is missing from the grid.

This can be demonstrated in the test/tree_expand.html page by running the following code:

syncGrid.store.put(syncGrid.store.get("OC"));
syncGrid.store.put(syncGrid.store.get("AU"));

or

1. Browse to test/tree_expand.html
2. Check the 'Visited' editor for Oceania
3. Click save
4. Check the 'Visited' editor for Australia
5. Click save

You'll notice a row is undefined error in the console and the Australia row is now missing.

[ghost]

Closing this as it's reportedly also fixed by #472 (and indeed, this sounds similar to the report in #467).