IsPlatformEnabled is false for RoundRectangle stroke shape of a Border, hence the parent element is not displayed on UI

[marius-jantea]

Hello,
I need to use a custom Layout component, and inside of it I want to place a Border that has a RoundRectangle stroke shape.

I will add bellow a sample code:

             `<compatibility:FlexLayout BackgroundColor="Pink"  MinimumHeightRequest="200" Grid.Row="2">
                <ScrollView BackgroundColor="Brown"
                            x:Name="ScrollViewInsideCascadeLayout"
                            Margin="0,0,0,6"
                            Orientation="Vertical"
                            VerticalScrollBarVisibility="Never">
                    <StackLayout  >
                        <StackLayout x:Name="OneLineCheckBoxCell"  ></StackLayout>  
                        <Border Stroke="#C49B33"
                                StrokeThickness="4"
                                StrokeShape="RoundRectangle 40,40,0,40"
                                x:Name="Border"
                                Background="#2B0B98"
                                Padding="16,8"
                                HorizontalOptions="Center">
                            <Label Text=".NET MAUI"
                                   TextColor="White"
                                   FontSize="18"
                                   FontAttributes="Bold" />
                        </Border>
                       <Label Text="hello"></Label>
                    </StackLayout>
                </ScrollView>
            </compatibility:FlexLayout>`

The problem is that the the scrollview inside the Flex Layout is not displayed.
I did some investigation, and it seems that the elements are not rendered, because of this condition (the LayotuChildren method is not called because the method returns false):
https://github.com/dotnet/maui/blob/main/src/Controls/src/Core/Layout.cs#L636

Does anyone have a workaround for this? If I set the visibility of the border to false, and set it to true when the ScrollView becomes visible, that works.
I tried setting the IsPlatformEnabled on the Border element, but that doesn't work, since the stroke shape element has the IsPlatformEnabled value false.

Do you have any other ideas / suggestions?

Possible related questions / issues (none with a solution):
#19274
#20534

[marius-jantea]

Setting the RoundRectangle.IsPlatformEnabled to true also seems to work. However, using that property outside of .NET Maui is not a recommandation.
((VisualElement)Border.StrokeShape).IsPlatformEnabled = true;

[marius-jantea]

The reason for not having the same issue when the StrokeShape is not defined on a border is because its default value is new Rectangle().
When we define a StrokeShape on a border, an OnPropertyChanged method is being called, and that adds the StrokeShape to a list of LogicalChildren (if we are not setting the StrokeShape, then the OnPropertyChanged event will not be triggered, hence the Rectangle won't be part of that LogicalChildren list, and the layout will be rendered).
Each element that belongs to the LogicalChildrenInternal list has to have the IsPlatformEnabled property set to true to be able to render the layout.