Expander content does not respect the given place from outside.

[JakobFerdinand]

Describe the bug

I´m using a ScrollViewer inside the content area of an Expander.
The available space for the expander itself is limited by a Grid.

If the Expanders content grows, the ScrollViewer should become active.
When using WPF-UI, the ScrollViewer does not get active an the content ist cut off.

To Reproduce

Here is the code to reproduce the Problem:

The MainWindow.xaml

<Window
    x:Class="ExpanderSample.MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:local="clr-namespace:ExpanderSample"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    Title="MainWindow"
    Width="800"
    Height="250"
    mc:Ignorable="d">
    <Grid Margin="10">
        <Expander
            VerticalAlignment="Top"
            Header="The expander problem description"
            IsExpanded="True">
            <Expander.Content>
                <Grid>
                    <ScrollViewer>
                        <TextBlock Margin="10">
                            When I start<LineBreak />
                            to write<LineBreak />
                            some longer text<LineBreak />
                            and I use<LineBreak />
                            WPF-UI<LineBreak />
                            the Expander<LineBreak />
                            starts to<LineBreak />
                            grow<LineBreak />
                            outside<LineBreak />
                            the grid<LineBreak />
                            area.<LineBreak />
                            Then the Scrollviewer<LineBreak />
                            does not work anymore<LineBreak />
                            🥺</TextBlock>
                    </ScrollViewer>
                </Grid>
            </Expander.Content>
        </Expander>
    </Grid>
</Window>

The App.xaml

<Application
    x:Class="ExpanderSample.App"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:local="clr-namespace:ExpanderSample"
    xmlns:ui="http://schemas.lepo.co/wpfui/2022/xaml"
    StartupUri="MainWindow.xaml">
    <Application.Resources>
        <ResourceDictionary>
            <ResourceDictionary.MergedDictionaries>
                <ui:ThemesDictionary Theme="Light" />
                <ui:ControlsDictionary />
            </ResourceDictionary.MergedDictionaries>
        </ResourceDictionary>
    </Application.Resources>
</Application>

To reproduce the error just copy that code into a new WPF application.
When you delete the activation of WFP-UI in the App.xamls ResourceDictionary you can test the expected behavior in plain WPF.

Expected behavior

I expect the content of the ScrollViewer to scroll like it does in plain WPF.

Screenshots

Without WPF-UI the ScrollViewer is doing it´s job:

With WPF-UI it´s not possible to scroll:

OS version

Windows 11 Enterprise
23H2

.NET version

.NET 8

WPF-UI NuGet version

3.0.4

Additional context

No response