Arrow keys navigation breaks on expanded inner nodes

[glukki]

Let's say we have root nodes A, B, C. Node B is collapsed, and has child nodes X1, X2. Node X1 is expanded, and hassle childs.

Now if you put focus on the node A, and push arrow down key, this happens:

1. B node get focused;
2. focus get lost. What actually happens — you navigate through children of node X1.

Expected:

1. B node get focused;
2. C node get focused.