When we drag an item from right tree to left tree, target t

When we drag an item
from right tree to left tree, target tree item does not highlight.

By default
the target item in drag-n-drop process is highlighted in target tree. You can
check the sample at scbr.com/docs/products/dhtmlxTree/index.shtml

Drop target
is not highlighted only if drag-n-drop to this node is not allowed. ( drag item
on its child ))

You can miss
highlighting in next cases:

a) Missed
dhtmlxtree.css

b) Using
“sibling” drag mode ( in such case another visual mark appears)

c) setting
custom dragIn handler which blocks drag-n-drop

d) some rare situation, when items in both tree has the same ID