[Qt] Widgets: Displaying artifacts of item selection in treelist while it is hidden by nearest column

Steps:
1. Run Editable Tree Model Example
2. Add 8-10 items as childs recursively by Ctrl+N
3. Select last added item
4. Resize nested column over selected item

Actual result:
Selection artifacts displayed on overlapped column.

Expected result:
No selection artifacts.

See attached screens.