Move node in first level of treeview generated error

[JamesC]

Tried to move treenode in first level of a treeview, exception raised with ACCESS_VIOLATION message. Code is shown below and it can be run properly in VCL application (change variables from TUniTreeNode to TTreeNode).

// Move up TreeNode in same level
procedure TFrameMachineGroup.UniToolButton1Click(Sender: TObject);
var
  tnSrc, tnDst: TUniTreeNode;
begin
  tnSrc := UniTreeView1.Selected;
  tnDst := tnSrc.GetPrevSibling;
  if tnDst <> nil then
    tnSrc.MoveTo(tnDst, naInsert);
  tnSrc.Selected := True;
end;

This code can run properly for other nodes under first level. Any mistake in my code? Thanks.

Testing with 1.90.0.1555 Trial.