Scroll box bar cannot be dragged when used in a widget component

The Scroll box cannot be scrolled by clicking and dragging the scroll bar when used as a widget component.

1. Download the attached project
2. Open the attached project
3. Play in the editor
4. Click the scroll box's scroll bar
5. Try to scroll the the scroll box using the scroll bar

Result: The Scroll box cannot be scrolled by clicking and dragging the scroll bar
Expected: The scroll box in the widget component would be able to be scrolled by clicking and dragging the scroll bar