600 Unpredictable movement in Tree if drag-drop object

[Scott_Y]

This has been excerpted from my comment in viewtopic.php?f=3&p=13968#p13968

(1) If I click-drag an object and hover it over a folder in the Tree, and that node is expandable, it will sometimes expand, sometimes not.
(2) If the target folder's name is out of view past the right edge of the Tree, the tree will sometimes scroll to the left so the name becomes visible.

I can't see a reason for the node sometimes expanding or scrolling, but sometimes not.
Can anyone explain this?

BTW, In Settings > View > Tree > Management page I have disabled
[ ] Auto Scroll Selected Node
[ ] Auto Expand On Click
but that doesn't seem to make a difference in the results.
(FC XE 600, Win7-64.)