Sometimes can't drop first item to last when only 2 items existing
I took me a while to get it but I think that in case where only 2 items exist, it will prevent from drag first item to last positon because the drop area doesn't seems reachable.
I made this reproduction
https://github.com/user-attachments/assets/139018f1-e99f-47e8-b40c-556056bcebb0
Sometimes it will work, but it depends on factors that aren't necessarily easy to achieve. You need to start dragging the element as close as possible to the boundingBox of the element; if you start dragging too low, it will be impossible. Then, depending on the distance from the top of the boundingBox of the selected element, the possible area to drop it below sometimes requires being very precise (a few pixels).
set min-height with css for tree, such as 100px.