<Swing Dev> [9] Review Request for 8129830: JTree drag/drop on lower half of last child of container incorrect

[Semyon Sadetsky]

Hello,

Please review fix for JDK9:

bug: https://bugs.openjdk.java.net/browse/JDK-8129830
webrev: http://cr.openjdk.java.net/~ssadetsky/8129830/webrev.00/

It is not possible to insert a tree node as a last child of any parent 
using Drag&Drop because the node is inserted as a sibling after the 
parent node.
To distinct those cases a solution is proposed: if drop point location 
is closer to the previous row then to insert into the last child 
position and insert into the sibling position otherwise.

--Semyon