Select layer on which the operation will be performed. It is important for project files. Thanks this it is possible to recognize which entry corespondents to which layer.
// Delphi public procedure SetGroup( const _layer : TObject ); override;
// C++ Builder public: virtual void SetGroup( TObject* const _layer );
|_layer||TObject||layer on which the operation will be performed; it is nil then operation will be performed on main entry ([TatukGIS] section)|