Not providing blurValue causes Exception: Please provide ShowCaseView context

[cirediew]

Not providing blurValue causes an exception when using a ReorderableListView

My code:

import 'package:flutter/material.dart';
import 'package:showcaseview/showcaseview.dart';
import 'package:test_app/my_list.dart';

class MyHomePage extends StatefulWidget {
  const MyHomePage({Key? key, required this.title}) : super(key: key);

  final String title;

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

class _MyHomePageState extends State<MyHomePage> {

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(widget.title),
      ),
      body: ShowCaseWidget(
        builder: Builder(
          builder: (_) => const MyList(),
        ),
      ),
    );
  }
}

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

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

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

class _MyListState extends State<MyList> {
  final List<int> _items = List<int>.generate(50, (int index) => index);
  final GlobalKey _one = GlobalKey();

  @override
  void initState() {
    super.initState();
    WidgetsBinding.instance!.addPostFrameCallback(
        (_) => ShowCaseWidget.of(context)!.startShowCase([_one]));
  }

  @override
  Widget build(BuildContext context) {
    final ColorScheme colorScheme = Theme.of(context).colorScheme;
    final Color oddItemColor = colorScheme.primary.withOpacity(0.05);
    final Color evenItemColor = colorScheme.primary.withOpacity(0.15);

    return ReorderableListView(
      children: <Widget>[
        for (int index = 0; index < _items.length; index++)
          if (index == 0)
            Showcase(
              key: _one,
              description: 'MyDescription',
              child: ListTile(
                key: Key('$index'),
                tileColor: _items[index].isOdd ? oddItemColor : evenItemColor,
                title: Text('Item ${_items[index]}'),
              ),
            )
          else
            ListTile(
              key: Key('$index'),
              tileColor: _items[index].isOdd ? oddItemColor : evenItemColor,
              title: Text('Item ${_items[index]}'),
            ),
      ],
      onReorder: (int oldIndex, int newIndex) {
        setState(() {
          if (oldIndex < newIndex) {
            newIndex -= 1;
          }
          final int item = _items.removeAt(oldIndex);
          _items.insert(newIndex, item);
        });
      },
    );
  }
}

══╡ EXCEPTION CAUGHT BY WIDGETS LIBRARY ╞═══════════════════════════════════════════════════════════
The following _Exception was thrown building
_OverlayEntryWidget-[LabeledGlobalKey<_OverlayEntryWidgetState>#8a869](dirty, dependencies:
[MediaQuery], state: _OverlayEntryWidgetState#1cbb4):
Exception: Please provide ShowCaseView context
The relevant error-causing widget was:
  MaterialApp MaterialApp:file:///Users/user/development/app/lib/main.dart:55:22
When the exception was thrown, this was the stack:
#0      ShowCaseWidget.of (package:showcaseview/src/showcase_widget.dart:66:7)
#1      _ShowcaseState.buildOverlayOnTarget (package:showcaseview/src/showcase.dart:266:52)
#2      _ShowcaseState.build.<anonymous closure> (package:showcaseview/src/showcase.dart:222:16)
#3      AnchoredOverlay.build.<anonymous closure>.<anonymous closure> (package:showcaseview/src/layout_overlays.dart:82:35)
#4      _OverlayEntryWidgetState.build (package:flutter/src/widgets/overlay.dart:208:34)
#5      StatefulElement.build (package:flutter/src/widgets/framework.dart:4705:27)
#6      ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4588:15)
#7      StatefulElement.performRebuild (package:flutter/src/widgets/framework.dart:4763:11)
#8      Element.rebuild (package:flutter/src/widgets/framework.dart:4311:5)
#9      StatefulElement.update (package:flutter/src/widgets/framework.dart:4795:5)
#10     Element.updateChild (package:flutter/src/widgets/framework.dart:3370:15)
#11     RenderObjectElement.updateChildren (package:flutter/src/widgets/framework.dart:5626:32)
#12     MultiChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:6284:17)
#13     Element.updateChild (package:flutter/src/widgets/framework.dart:3370:15)
#14     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4613:16)
#15     StatefulElement.performRebuild (package:flutter/src/widgets/framework.dart:4763:11)
#16     Element.rebuild (package:flutter/src/widgets/framework.dart:4311:5)
#17     BuildOwner.buildScope (package:flutter/src/widgets/framework.dart:2578:33)
#18     WidgetsBinding.drawFrame (package:flutter/src/widgets/binding.dart:882:21)
#19     RendererBinding._handlePersistentFrameCallback (package:flutter/src/rendering/binding.dart:363:5)
#20     SchedulerBinding._invokeFrameCallback (package:flutter/src/scheduler/binding.dart:1145:15)
#21     SchedulerBinding.handleDrawFrame (package:flutter/src/scheduler/binding.dart:1082:9)
#22     SchedulerBinding._handleDrawFrame (package:flutter/src/scheduler/binding.dart:996:5)
#26     _invoke (dart:ui/hooks.dart:150:10)
#27     PlatformDispatcher._drawFrame (dart:ui/platform_dispatcher.dart:270:5)
#28     _drawFrame (dart:ui/hooks.dart:114:31)
(elided 3 frames from dart:async)
════════════════════════════════════════════════════════════════════════════════════════════════════

It works fine when I do provide a blurValue like so:

Showcase(
              key: _one,
              description: 'MyDescription',
              blurValue: 0.0,
              child: ListTile(
                key: Key('$index'),
                tileColor: _items[index].isOdd ? oddItemColor : evenItemColor,
                title: Text('Item ${_items[index]}'),
              ),
            )