BugFix: BUG: Since the roots of the trees are hidden, if a tree was empty at the start it's root defaulted to it's shrunken state, and since noting would trigger it's expansion, and the user can't click it's state's control to expand it manually, it looked empty and as if noting happened even if a node was added to the tree. --- FIX: Now the last node sent to another tree is automatically expanded, fixing the bug and making the last node exchanged always be visible.