Greetings from Syncfusion support.
We have checked your reported query about TreeView scrollbar. We suspect that the below cases are your requirement.
1. While drag and drop from TreeView to another component (like listview, scheduler.,) the dragging element is maintained in corresponding TreeView.
2. When scroll the TreeView from the end, drag a last element and drop to another TreeView first position, the scroller in that TreeView is maintained in same position.
For your reference, we have prepared a sample for both the above cases.
If we have misunderstood your requirement, can you please share the additional details regarding your requirement, it will helpful for us to resolve your issue earlier.