var
  Block: TBeginEndBlock;
  Pt: TFloatPoint;
begin
  Block := TBeginEndBlock.Create;
  Pt.X := 200;
  Pt.Y := 200;
  Block.Vertex[2] := Pt;
  Pt.X := 100;
  Pt.Y := 100;
  Block.Vertex[1] := Pt;
  VisualContainer.AddObject(Block);

 Ins

Type
  TDisplayObj = class
  Public
    Procedure OnStart(X, Y: LongInt);
    Procedure OnMove(X, Y: LongInt);
    Procedure OnEnd(Align: LongInt = 0);
  End;

  // Объект рассчитан на конкретную задачу, вывода блок-схем.

{$IFDEF SPACEANGLE}
procedure TECADPluginObject.RotatePoint(Point1, Point2: TECADFloatPoint);
begin
  Host.RotatePoint(Point1, Point2);
end;
{$ENDIF}

 Ins

TVisualContainer = class(TCustomControl, ICoordConvert)
...
  public
    procedure Group;
    procedure UnGroup;
...
end;
// Для примера группирую все объекты в конейнере
procedure TVisualContainer.Group;
var
   i : integer;
begin
  FCurrentObject := TGroup.Create;
  FCurrentObject.OnChange := ObjectChanged;
  Selected := FObjects.Add(FCurrentObject);
  for i := 1 to FObjects.Count-1 do begin
    if TBaseVisualObject(FObjects[i-1]).Parent = nil then (FCurrentObject as TGroup).AddObject(TBaseVisualObject(FObjects[i-1]));
  end;
end;

procedure TVisualContainer.UnGroup;
var
   i : integer;
begin
if FCurrentObject is TGroup then begin
    Selected := -1;
    i := FObjects.IndexOf(FCurrentObject);
    FObjects.Delete(i);
    Invalidate;
end;
end;

  TGroup = class(TRectVisualObject)
  private
    FChildren : TObjectList;
    procedure UpdatePoints;
    procedure VOCMove(var Command: TVOCMove); message VOC_MOVE;
  public
    constructor Create; override;
    destructor Destroy; override;
    procedure AddObject(AObject:TBaseVisualObject);
  end;

constructor TGroup.Create;
begin
inherited Create;
FChildren := TObjectList.Create(True);
end;

destructor TGroup.Destroy;
var
j : integer;
begin
  for j := 1 to FChildren.Count do TBaseVisualObject(FChildren[j-1]).Parent := nil;
  inherited Destroy;
end;

procedure TGroup.AddObject(AObject:TBaseVisualObject);
begin
FChildren.Add(AObject);
AObject.FParent := Self;
UpdatePoints;
end;

procedure TGroup.UpdatePoints;
var i,j: integer;
    P1,P2:TFloatPoint;
begin
  if FChildren.Count = 0 then exit;
  P1 := TBaseVisualObject(FChildren[0]).BasePoints[0];
  P2 := TBaseVisualObject(FChildren[0]).BasePoints[0];
  BeginUpdate;
  for j := 1 to FChildren.Count do begin
    for i:=1 to TBaseVisualObject(FChildren[j-1]).BasePointsCount do
    begin
      P1.x := min(P1.x,TBaseVisualObject(FChildren[j-1]).BasePoints[i-1].x);
      P1.y := min(P1.y,TBaseVisualObject(FChildren[j-1]).BasePoints[i-1].y);
      P2.x := max(P2.x,TBaseVisualObject(FChildren[j-1]).BasePoints[i-1].x);
      P2.y := max(P2.y,TBaseVisualObject(FChildren[j-1]).BasePoints[i-1].y);
    end;
  end;
  BasePoints[0] := P1;
  BasePoints[1] := P2;
  EndUpdate;
end;

procedure TGroup.VOCMove(var Command: TVOCMove);
var
  i: Integer;
begin
  inherited;
  for i := 1 to FChildren.Count do  TBaseVisualObject(FChildren[i-1]).SendCommand(Command.CmdID, longint(Command.DeltaX), longint(Command.DeltaY));
end;

// создаются два блока типа TActionBlock
// добавляется кнопка и ее обработчик
// некоторые методы пришлось сделать public, но это на скорую руку

procedure TForm1.ToolButton11Click(Sender: TObject);
var
  Pos: TFloatPoint;

begin

{}
  VisualContainer1.ObjectType := TActionBlock;
  VisualContainer1.StartConstruct;
  TActionBlock(VisualContainer1.SelectedObject).Text := 'Block1';
  VisualContainer1.ScreenToLog(100, 100, Pos.X, Pos.Y);
  VisualContainer1.SelectedObject.SendCommand(VOC_CONSTRUCTPOINT, 0, Longint(@Pos));
  VisualContainer1.ScreenToLog(200, 120, Pos.X, Pos.Y);
  VisualContainer1.SelectedObject.SendCommand(VOC_CONSTRUCTPOINT, 0, Longint(@Pos));
  VisualContainer1.FinishConstruct;
{}
{}
  VisualContainer1.ObjectType := TActionBlock;
  VisualContainer1.StartConstruct;
  TActionBlock(VisualContainer1.SelectedObject).Text := 'Block2';
  VisualContainer1.ScreenToLog(220, 100, Pos.X, Pos.Y);
  VisualContainer1.SelectedObject.SendCommand(VOC_CONSTRUCTPOINT, 0, Longint(@Pos));
  VisualContainer1.ScreenToLog(320, 120, Pos.X, Pos.Y);
  VisualContainer1.SelectedObject.SendCommand(VOC_CONSTRUCTPOINT, 0, Longint(@Pos));
  VisualContainer1.FinishConstruct;
{}

end;

...........

function TVisualContainer.FindObject(X, Y: Integer; var HitTest: Cardinal): Integer;
...
    HitTest := TBaseVisualObject(FObjects[i]).SendCommand(VOC_HITTEST,
      Longint(Self as ICoordConvert), Longint(@Params));
...

...........

procedure TBaseVisualObject.VOCHitTest(var Command: TVOCHitTest);
begin
  Command.Result := HT_OUT;
end;

FCanvas.Brush.Style := bsSolid;

FCanvas.Brush.Style := bsClear;

 Ins