Reference TButton

  TButton = class(TWidget)
  protected
    procedure DoClick; override;
  public
    { When true the button stays down when clicked and comes up when clicked
      again }
    property CanToggle: Boolean read FCanToggle write FCanToggle;
    { True while a button which can toggle is down }
    property Down: Boolean read FDown write SetDown;
    { Only one of the toggle buttons with the same parent and the same group
      above zero is down at a time }
    property Group: Integer read FGroup write FGroup;
    property OnChange;
    property OnClick;
    property OnKeyDown;
    property OnMouseDown;
    property OnMouseMove;
    property OnMouseUp;
  end;