How to remove space in vertical for the showMenu function?

I use the showMenu function to show menus with dialog.My code is

      const width = 100.0;      const height = 40.0;      await showMenu(        items: [          PopupMenuItem(padding: EdgeInsets.zero, child: Container(width: width, height: height, color: Colors.blue, child: const Text('test 1'))),          PopupMenuItem(padding: EdgeInsets.zero, child: Container(width: width, height: height, color: Colors.blue, child: const Text('test 2'))),        ],        context: context,        position: const RelativeRect.fromLTRB(0, 0, 0, 0),        constraints: const BoxConstraints(maxWidth: width, maxHeight: height * 2),        shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(5)),        color: Colors.red,      );

I tried to fit it by setting the maxWidth and maxHeight of the constraints property in the showMenu, the horizontal is working but the vertical still has space between menus.