flutter_layout_grid nested grid overflow

main.dart

import 'package:flutter/material.dart';
import 'package:flutter_layout_grid/flutter_layout_grid.dart';

void main() {
  runApp(const MyApp());
}

class MyApp extends StatelessWidget {
  const MyApp({Key? key}) : super(key: key);

  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return const MaterialApp(
      title: 'Nested Grid Demo',
      home: MyHomePage(),
    );
  }
}

class MyHomePage extends StatefulWidget {
  const MyHomePage({Key? key}) : super(key: key);

  @override
  State<MyHomePage> createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text('Nested Grid Demo'),
      ),
      // Use a column so that outer grid has no pre-determined height.
      body: Column(
        mainAxisSize: MainAxisSize.min,
        children: [
          const Divider(),
          const Text('OuterGrid with nested InnerGrid:'),
          const OuterGrid(),
          const SizedBox(height: 30),
          // Just to check the height calculation, wrap the inner grid in a colored container.
          // Seems to be correct when not nested.
          const Divider(),
          const Text('InnerGrid not nested:'),
          Container(color: Colors.amber, child: const InnerGrid()),
        ],
      ),
    );
  }
}

class OuterGrid extends StatelessWidget {
  const OuterGrid({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return LayoutGrid(
      areas: '''
      r1
      r2
     ''',
      columnSizes: [1.fr],
      rowSizes: const [auto, auto],
      columnGap: 0,
      // Note that the InnerGrid's Row 3 overflows into this gap.
      rowGap: 30,
      children: [
        Container(
          color: Colors.lightBlue,
          child: const InnerGrid(),
        ).inGridArea('r1'),
        Container(
          color: Colors.lightGreen,
          height: 200,
        ).inGridArea('r2'),
      ],
    );
  }
}

class InnerGrid extends StatelessWidget {
  const InnerGrid({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return LayoutGrid(
      areas: '''
      r1
      r2
      r3
     ''',
      columnSizes: [1.fr],
      rowSizes: const [auto, auto, auto],
      columnGap: 0,
      rowGap: 10,
      children: [
        const Text('Row 1').inGridArea('r1'),
        const Text('Row 2').inGridArea('r2'),
        const Text('Row 3').inGridArea('r3'),
      ],
    );
  }
}