Flickering Issue When Toggling WebView Visibility in Grid Layout on Android

kellymmcd commented 1 month ago

Description

In Android when changing the visibility of a WebView within a grid I'm getting an issue where the elements underneath the grid start flickering as seen in video below.

https://github.com/user-attachments/assets/12dafdd7-398b-448b-9b7e-821bfa1d8cc5

Steps to Reproduce

Create a new .NET MAUI app.

Add the following XAML code in MainPage.xaml:


<ScrollView>
<Grid RowDefinitions="50,Auto,185,40"
    Padding="30,0">
    <Button
        Grid.Row="0"
        Text="Click me" 
        Clicked="OnClicked"
        HorizontalOptions="Fill" />
    <WebView
           x:Name="webView"
           IsVisible="False"
           Grid.Row="1">
        <WebView.Source>
            <HtmlWebViewSource>
                <HtmlWebViewSource.Html>
                    <![CDATA[
                    <HTML>
                    <BODY>
                    <H1>.NET MAUI</H1>
                    <P>Welcome to WebView.</P>
                    </BODY>
                    </HTML>
                    ]]>
                </HtmlWebViewSource.Html>
            </HtmlWebViewSource>
        </WebView.Source>
    </WebView>
    <Image
         Grid.Row="2"
         Source="dotnet_bot.png"
         HeightRequest="185"
         Aspect="AspectFit"
         SemanticProperties.Description="dot net bot in a race car number eight" />

    <Label
         Grid.Row="3"
         Text="Hello, World!"
         Style="{StaticResource Headline}"
         SemanticProperties.HeadingLevel="Level1" />
</Grid>
</ScrollView>


3. In the code-behind (MainPage.xaml.cs), add the following method:

private void OnClicked(object sender, EventArgs e) { webView.IsVisible = !webView.IsVisible; }


4. Run the app on a Android physical device or an emulator
5. Click the button to toggle the WebView visibility on and off.

### Link to public reproduction project repository

_No response_

### Version with bug

8.0.80 SR8

### Is this a regression from previous behavior?

Not sure, did not test other versions

### Last version that worked well

Unknown/Other

### Affected platforms

Android

### Affected platform versions

_No response_

### Did you find any workaround?

Setting a height request on the WebView prevents this from happening. However in my scenario I don't know the height of the contents in the WebView to set this. 

### Relevant log output

_No response_

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