AdvTreeView Nodes Enumeration

VCL TMS VCL UI Pack
7

Hi!

Found some problems with simple using of TAdvTreeView... Just Adding and removing...

1. Creates three root nodes by AddButton. 
https://imgur.com/lCWZO3G

2. Adding to first root node (Row = 0) one child nodes by selection and AddButton .
https://imgur.com/QuNBNJo

3. Deleting first root node by DelButton.
https://imgur.com/UDsf5aC

4. Trying to add root node by AddButton... But there is "Access Violation..."
https://imgur.com/opb8VpL

What i'm doing wrong?

There is code:

//---------------------------------------------------------------------------
void __fastcall TForm1::FormCreate(TObject *Sender)
{
AdvTreeView1->BeginUpdate();
AdvTreeView1->ClearNodes();
AdvTreeView1->ClearColumns();

AdvTreeView1->Columns->Add()->Text = "1 col";
AdvTreeView1->Columns->Add()->Text = "2 col";
AdvTreeView1->Columns->Add()->Text = "3 col";
AdvTreeView1->EndUpdate();
}
//---------------------------------------------------------------------------
void __fastcall TForm1::AddButtonClick(TObject *Sender)
{
TAdvTreeViewNode *tn;
if(!AdvTreeView1->FocusedNode){
tn = AdvTreeView1->AddNode();
}
else{
tn = AdvTreeView1->AddNode(AdvTreeView1->FocusedNode);
}
AdvTreeView1->ExpandAll();
}
//---------------------------------------------------------------------------
void __fastcall TForm1::DelButtonClick(TObject *Sender)
{
TAdvTreeViewVirtualNode tvn = ((TAdvTreeViewOpen)AdvTreeView1)->GetNodeForRow(0);
if(tvn){
AdvTreeView1->RemoveNode(tvn->Node);
}
}
//---------------------------------------------------------------------------

void __fastcall TForm1::AdvTreeView1AfterDrawNode(TObject *Sender, TCanvas *ACanvas,
  TRectF &ARect, TAdvTreeViewVirtualNode *ANode)
{
ANode->Node->Text[0] = ANode->Row;
}
//---------------------------------------------------------------------------