treeviewitems with childrens aren't highlighted on hover #495

Describe the bug
When you add TreeView and populate it with some nodes which contains childs you can see that nodes with childrens aren't highlighted when you hover on em with mouse. items without childs are highlighted on hover properly.

To Reproduce
Steps to reproduce the behavior:

1. Add TreeView
2. Populate it with some nodes (including nodes, which contains some childs)
3. Test app (try hover on different nodes: with/without childs)

Expected behavior
Nodes with childs should be highlighted on hover too, as items without childs are highlighted.

Environment (please complete the following information):

• Version 2.5.0.2 (Latest on nuget)

Additional context
I already reported that problem on HandyControls repo, it was fixed, but version with fix wasn't uploaded to nuget.