FIX. RadGridView is slow when using self-referencing hierarchy with a large number of rows
1. Create a new project with RadGridView.
2. Setup self-referencing hierarchy with 1000 rows and 14 columns.
3. Run the project.
4. Scroll up and down several times.
5. Resize the window.
6. Scroll up and down again.
7. RadGridView will hang.