Help with Treeview MoveTo (D3 NOT D4)

I have not been able to implement Drag&Drop in a treeview. I have a
test app with a treeview and several nodes, and using the code in
Delphi help under moveto, I only get the drag icon with the NOT sign
when I try to move a node.

I know, from reading other messages that the code works, so I must
have overlooked something. (Dragmode is set for automatic)
What did I forget?

I am using Delphi 3, not 4,which I know has a problem.
//----------------
procedure TForm1.TreeView1DragDrop(Sender, Source: TObject; X, Y:
Integer);
var
  AnItem: TTreeNode;
  AttachMode: TNodeAttachMode;
  HT: THitTests;
begin
  if TreeView1.Selected = nil then Exit;
  HT := TreeView1.GetHitTestInfoAt(X, Y);
  AnItem := TreeView1.GetNodeAt(X, Y);
  if (HT - [htOnItem, htOnIcon, htNowhere, htOnIndent] <> HT) then
  begin
    if (htOnItem in HT) or (htOnIcon in HT) then AttachMode :=
naAddChild
    else if htNowhere in HT then AttachMode := naAdd
    else if htOnIndent in HT then AttachMode := naInsert;
    TreeView1.Selected.MoveTo(AnItem, AttachMode);
  end;
end;
//------------------

I'll appreciate any suggestions.
Ken