Bug display in TreeGrid

Flow
1

I have a problem with your add-on Vaadin.

I have a grid in a window. The grid contains two parent node and each parent node contains some child node.

https://cloud.githubusercontent.com/assets/25502578/22545039/7eec3ab0-e937-11e6-9ada-45080998d4eb.png

When all nodes are fold up and I unfold one node, I can have a bug display in treegrid like this

https://cloud.githubusercontent.com/assets/25502578/22545200/14421e2c-e938-11e6-84e3-ebb08338876d.png
https://cloud.githubusercontent.com/assets/25502578/22545219/23cd5e24-e938-11e6-9cec-6e6bdbe2e40c.png

Nevertheless, I don’t have this problem when the grid is not in a window and when I use Chrome. The problem is just with IE.

https://cloud.githubusercontent.com/assets/25502578/22545561/86d8f040-e939-11e6-9e18-faed465d457e.png

Sincerely.
30501.zip (13.1 MB)

2

For reference, the issue about this on Github:
https://github.com/vaadin/tree-grid/issues/13