Pages retained in memory when using DynamicResource Grid style

[duffh]

Description

In a .NET MAUI Shell app running on Windows it looks like pages referencing DynamicResource Grid styles are held in memory after navigating to and then away from the page. This results in an increase in memory over time as pages are opened and closed.

Steps to Reproduce

Setup

1. Create new Maui app. File -> New Solution -> Maui App
2. Add the following style to Styles.xaml:

<Style x:Key="GridContainer" TargetType="Grid">
    <Setter Property="Grid.RowDefinitions" Value="Auto,*" />
    <Setter Property="Grid.ColumnDefinitions" Value="*,Auto" />
</Style>

3. Create two new MAUI ContentPages StyledPage and UnstyledPage
4. Add a Grid element to both of the newly created pages
   4a. To the StyledPage add:

   <Grid Style="{DynamicResource GridContainer}">
    <Label 
        Grid.Row="0" Grid.ColumnSpan="2"
        Text="This is the first row"
        VerticalOptions="Center" 
        HorizontalOptions="Center" />
    <Label 
        Grid.Row="1" Grid.ColumnSpan="2"
        Text="This is the second row"
        VerticalOptions="Center" 
        HorizontalOptions="Center" />
   </Grid>
   

   4b. To the UnstyledPage add:

   <Grid RowDefinitions="Auto, *" ColumnDefinitions="*, Auto">
    <Label 
        Grid.Row="0" Grid.ColumnSpan="2"
        Text="This is the first row"
        VerticalOptions="Center" 
        HorizontalOptions="Center" />
    <Label
        Grid.Row="1" Grid.ColumnSpan="2"
        Text="This is the second row"
        VerticalOptions="Center" 
        HorizontalOptions="Center" />
   </Grid>
   

5. Add a Button to the MainPage with a clicked event await Navigation.PushAsync(new StyledPage());
6. Add a Button to the MainPage with a clicked event await Navigation.PushAsync(new UnstyledPage());
7. Add a Button to the MainPage with a clicked event GC.Collect();

Testing

1. Run the app targeting Windows
2. Navigate to the StyledPage
3. Click the back button
4. Click the GC Collect button
5. Take a snapshot of the memory usage
6. Navigate to the UnstyledPage
7. Click the back button
8. Click the GC Collect button
9. Take a snapshot of the memory usage
10. Repeat as many times as necessary

Result: Looking at the memory usage snapshots the number of instances of StyledPage in memory increases with the number of times the page has been opened.

Expected: The page should no longer exist in memory after navigating away, the number of instances in memory should not increase as the page is repeatedly opened. This works correctly for the UnstyledPage.

Link to public reproduction project repository

https://github.com/duffh/MauiStylesMemoryLeakTestApp

Version with bug

8.0.0-preview.5.8529

Last version that worked well

Unknown/Other

Affected platforms

Windows, I was not able test on other platforms

Affected platform versions

Windows SDK 10.0.19041.0

Did you find any workaround?

No response

Relevant log output

No response

[jsuarezruiz]

cc @jonathanpeppers

[jonathanpeppers]

@duffh does this look like the exact same issue as this one?

#16145

[duffh]

Looks like the same issue to me, thanks for taking a look!

[jonathanpeppers]

I wasn't aware of this issue filed -- and I just happened to find the problem in another sample, thanks!