TabViewItem contents not stretching properly.

[ghost]

I am attempting to incorporate a WebView2 within a TabViewItem. However, I am facing an issue where the WebView2 does not appear unless I explicitly set the Width and Height of its parent element. The HorizontalAlignment="Stretch" and VerticalAlignment="Stretch" properties do not seem to work for any child elements of the TabViewItem.

`

<Grid>
    <TabView>
        <TabView.TabItems>
            <TabViewItem Header="Tab 1">
                <Grid HorizontalAlignment="Stretch" VerticalAlignment="Stretch" Width="800" Height="800">
                        <controls:WebView2 x:Name="MyWebView"  Source="https://www.microsoft.com"
                        HorizontalAlignment="Stretch"
                        VerticalAlignment="Stretch" />
                </Grid>
            </TabViewItem>
            <TabViewItem Header="Tab 2">
                <Grid Background="LightBlue">
                    <TextBlock Text="Content of Tab 2" FontSize="20" HorizontalAlignment="Center" VerticalAlignment="Center"/>
                </Grid>
            </TabViewItem>
            <TabViewItem Header="Tab 3">
                <Grid Background="LightGreen">
                    <TextBlock Text="Content of Tab 3" FontSize="20" HorizontalAlignment="Center" VerticalAlignment="Center"/>
                </Grid>
            </TabViewItem>
        </TabView.TabItems>
    </TabView>
</Grid>

`