🐛 DatePicker throws Exception: A RenderListWheelViewport was mutated in _RenderLayoutBuilder.performLayout.

[pamtbaau]

Describe the bug
A clear and concise description of what the bug is.

When changing the value of a DatePicker by scrolling the date, an exception is thrown when setState() is called in onChanged.

Workaround until fixed:
Wrap setState() inside a Future.delayed():

    onChanged: (value) {
      Future.delayed(const Duration(milliseconds: 500), () {
        setState(() {
          selected = value;
        });
      });
    },

To Reproduce
Steps to reproduce the behavior:

• Create fresh Flutter app using cli
• Add the following dependency:

  fluent_ui:
    git: https://github.com/bdlukaa/fluent_ui.git
  

• Update main.dart as follows:

  import 'package:fluent_ui/fluent_ui.dart';
  
  void main() async {
    runApp(const MyApp());
  }
  
  class MyApp extends StatelessWidget {
    const MyApp({super.key});
  
    @override
    Widget build(BuildContext context) {
      return FluentApp(
        title: 'Bug issue',
        home: NavigationView(
          pane: NavigationPane(
            selected: 0,
            displayMode: PaneDisplayMode.compact,
            items: [
              PaneItem(
                icon: const Icon(FluentIcons.home),
                title: const Text('Home'),
                body: Container(
                  alignment: Alignment.center,
                  child: const DateWidget(),
                ),
              ),
            ],
          ),
        ),
      );
    }
  }
  
  class DateWidget extends StatefulWidget {
    const DateWidget({super.key});
  
    @override
    State<DateWidget> createState() => DateWidgetState();
  }
  
  class DateWidgetState extends State<DateWidget> {
    DateTime selected = DateTime.now();
  
    @override
    void initState() {
      super.initState();
    }
  
    @override
    Widget build(BuildContext context) {
      return DatePicker(
        selected: selected,
        fieldOrder: const [
          DatePickerField.year,
          DatePickerField.month,
          DatePickerField.day,
        ],
        onChanged: (value) {
          setState(() {
            selected = value;
          });
        },
      );
    }
  }
  

• Run app in debug mode
  • Change date by scrolling the year, month or day value.
  • Error is thrown.
• Run app in release mode
  • Change date by scrolling the year, month or day value.
  • All goes well.

Expected behavior
A clear and concise description of what you expected to happen.

Screenshots
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Additional context
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[bdlukaa]

We are calling onChanged before popping the picker. I believe changing this order fixes this issue.

[MiaraSystems]

I see the same issue.