Bug: some elements expanding upwards, some downwards

[lff5]

Hi.
Video explains it all:

I am expecting the panel to open downward, because if there is a text preview then at expanding the preview part would remain in place (that should be the default behavior), but in my app it mostly opens upward.

Why is 1-99 opening upward and 100 and up opening downward? Is it a bug?
Is there any way to control in which direction the expandable panel should open?

Code to reproduce.

scrollable_positioned_list: ^0.2.0-nullsafety.0
expandable: ^5.0.1

import 'package:flutter/material.dart';
import 'package:scrollable_positioned_list/scrollable_positioned_list.dart';
import 'dart:math';
import 'package:expandable/expandable.dart';

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: MyHomePage(),
    );
  }
}

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

  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  List<int> heights = [];
  Key key = UniqueKey();
  int startIndex = 100;
  final controller = ItemScrollController();

  @override
  void initState() {
    super.initState();
    Random random = new Random();
    for (int i = 0; i < 500; i++) heights.add(random.nextInt(100) + 30);
  }

  Widget itemBuilderInstant(BuildContext context, int index) {
    final controller = ExpandableController();
    return GestureDetector(
      onTap: controller.toggle,
      child: ExpandablePanel(
        controller: controller,
        collapsed: Container(
            color: index % 5 == 0 ? Colors.amber : Colors.white,
            height: heights[index].toDouble(),
            child: Text("Index $index, ${heights[index]}")),
        expanded: Container(
            color: index % 5 == 0 ? Colors.amber : Colors.white,
            height: heights[index].toDouble() * 2,
            child: Text("Index $index, ${heights[index]}")),
      ),
    );

  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      floatingActionButton: TextButton(
          onPressed: () {
            controller.scrollTo(
                index: Random().nextInt(heights.length),
                duration: Duration(milliseconds: 500));
            Future.delayed(Duration(milliseconds: 200)).then((value) {
              setState(() {
                key = UniqueKey();
                startIndex = Random().nextInt(heights.length);
              });
            });
          },
          child: Text("scroll and swap")),
      floatingActionButtonLocation: FloatingActionButtonLocation.centerTop,
      body: ScrollablePositionedList.builder(
          itemScrollController: controller,
          initialScrollIndex: startIndex,
          key: key,
          itemCount: heights.length,
          itemBuilder: itemBuilderInstant),
    );
  }
}

Flutter doc

[✓] Flutter (Channel stable, 2.0.6, on Mac OS X 10.15.7 19H524 darwin-x64, locale en-EE)
[✓] Android toolchain - develop for Android devices (Android SDK version 30.0.3)
[✓] Xcode - develop for iOS and macOS
[✓] Chrome - develop for the web
[✓] Android Studio (version 4.1)
[✓] VS Code (version 1.56.2)
[✓] Connected device (2 available)

[AlienKevin]

I encountered the exact same issue when using flutter-expandable in conjunction with scrollable_positioned_list. I found a solution by using another plugin called scroll-to-index instead of scrollable_positioned_list. Scroll-to-index is more flexible as it works on any scrollable widgets and it doesn't seem to interfere with flutter-expandable. See example code.