FlyoutPage CollapsedPaneWidth is not working

[devanathan-vaithiyanathan]

Description

When CollapseStyle is set to Partial, the flyout always collapses to the default width of 48px, even if a different CollapsedPaneWidth value is assigned.

Steps to Reproduce

1.Run the below code on Windows Platform

using Microsoft.Maui.Controls;
using Microsoft.Maui.Controls.PlatformConfiguration.WindowsSpecific;
using Microsoft.Maui.Graphics;

namespace MauiApp1;

public class MainPage: FlyoutPage
{
    private Label _label;

    public MainPage()
    {
        // Windows-specific collapse config
        this.On<Microsoft.Maui.Controls.PlatformConfiguration.Windows>()
            .SetCollapseStyle(CollapseStyle.Partial);

        this.On<Microsoft.Maui.Controls.PlatformConfiguration.Windows>()
            .CollapsedPaneWidth(100);

        FlyoutLayoutBehavior = FlyoutLayoutBehavior.Popover;

        // Flyout
        var flyoutPage = new ContentPage
        {
            Title = "Master",
            BackgroundColor = Colors.Blue
        };

        var btn = new Button
        {
            Text = "Change",
            AutomationId = "FlyoutItem",
            HorizontalOptions = LayoutOptions.Start,
            VerticalOptions = LayoutOptions.Center
        };

        btn.Clicked += (s, e) =>
        {
            this.On<Microsoft.Maui.Controls.PlatformConfiguration.Windows>()
                .CollapsedPaneWidth(300);

            _label.Text = "CollapsedPaneWidth set to 300";
        };

        flyoutPage.Content = new VerticalStackLayout
        {
            Padding = 12,
            Children = { btn }
        };

        // Detail
        var detailPage = new ContentPage
        {
            Title = "Detail",
            BackgroundColor = Colors.LightYellow
        };

        _label = new Label
        {
            Text = "Test for CollapsedPaneWidth",
            AutomationId = "CollapsedPaneLabel",
            TextColor = Colors.Black
        };

        detailPage.Content = new VerticalStackLayout
        {
            Padding = 12,
            Spacing = 16,
            Children =
            {
                new Label
                {
                    Text = "Welcome to .NET MAUI!",
                    TextColor = Colors.Black,
                    HorizontalOptions = LayoutOptions.Center
                },
                _label
            }
        };

        Flyout = flyoutPage;
        Detail = detailPage;
    }
}

Link to public reproduction project repository

No response

Version with bug

10.0.30

Is this a regression from previous behavior?

No, this is something new

Last version that worked well

Unknown/Other

Affected platforms

Windows

Affected platform versions

Windows 11

Did you find any workaround?

No response

Relevant log output

[MihuBot]

I'm a bot. Here is a possible related and/or duplicate issue (I may be wrong):

• Flyout Page SetCollapseStyle doesn't have any change #18200

[LogishaSelvarajSF4525]

This issue has been validated in Visual Studio 18.1.1 with MAUI versions (10.0.0, 10.0.10 & 10.0.30). It can be reproducible on Windows platform.