void __fastcall TFormaVvod::TreeView1Expanded(TObject *Sender, 
      TTreeNode *Node) 
{ 
Node->ImageIndex =  0; 
Node->SelectedIndex = 1; 
} 
//---------------------------------------------------------------------- ----- 
void __fastcall TFormaVvod::TreeView1Collapsed(TObject *Sender, 
      TTreeNode *Node) 
{ 
Node->ImageIndex =  1; 
Node->SelectedIndex = 0; 
}

TTreeNode *Node1;
Node1=TreeView1->Items->AddChild(NULL,"Типа новый элемент");
Node1->ImageIndex=0;
Node->SelectedIndex=1;

procedure TForm1.dxDBTreeList1GetImageIndex(Sender: TObject;
  Node: TdxTreeListNode; var Index: Integer);
begin
 if Node.Expanded then
  index := 1
 else
  index := 0;
end;

procedure TForm1.dxDBTreeList1GetSelectedIndex(Sender: TObject;
  Node: TdxTreeListNode; var Index: Integer);
begin
  Index:= Node.ImageIndex;
end;