Not working shared size scope, Shared size scrope is converting * to Auto

Tried to make a list of tasks running in background which has a style similar to what MenuItem has, but found that shared size doesn’t work at all, but applies when and only when it is reset. Here’s a gif showing how it behaves:

To make a minimal repro use the following XAML (cut off of the original):

<ScrollViewer>
  <ItemsRepeater
    x:Name="AllOperations"
    Grid.IsSharedSizeScope="True"
    Items="{Binding Operations}"
    KeyboardNavigation.TabNavigation="Continue">

    <ItemsRepeater.Layout>
      <StackLayout Orientation="Vertical" Spacing="8" />
    </ItemsRepeater.Layout>

    <ItemsRepeater.ItemTemplate>
      <DataTemplate DataType="status:Operation">
        <Button Height="{StaticResource StatusBarHeight}">

          <Grid>

            <Grid.ColumnDefinitions>
              <ColumnDefinition Width="*" SharedSizeGroup="OperationName" />
              <ColumnDefinition Width="{StaticResource StatusBarIconWidth}" />
              <ColumnDefinition Width="{StaticResource StatusBarProgressWidth}" />
              <ColumnDefinition Width="{StaticResource StatusBarIconWidth}" />
            </Grid.ColumnDefinitions>

            <TextBlock
              Grid.Column="0"
              Grid.ColumnSpan="2"
              Margin="4,0"
              Text="{Binding Name}"
              TextTrimming="CharacterEllipsis" />

            <controls:ProgressBar
              Grid.Column="2"
              Margin="4,0"
              HorizontalAlignment="Stretch"
              Maximum="1"
              Value="{Binding Progress}" />

            <TextBlock
              Grid.Column="3"
              Margin="4,0"
              IsVisible="{Binding !#PART_OperationStatus.IsVisible}"
              Text="{Binding Progress, StringFormat=\{0:P0\}}"
              TextAlignment="Center" />

            <Border
              x:Name="PART_OperationStatus"
              Grid.Column="3" />

          </Grid>

        </Button>
      </DataTemplate>
    </ItemsRepeater.ItemTemplate>

  </ItemsRepeater>
</ScrollViewer>

private class Operation
{
    public string Name { get; set; }

    public double? Progress { get; set; }
}

[wieslawsoltes]

Shared size scrop is converting * to Auto

Same as in WPF https://docs.microsoft.com/en-us/dotnet/api/system.windows.controls.grid.issharedsizescope?view=net-5.0#remarks

Columns and rows participating in size sharing do not respect Star sizing. In this scenario, Star sizing is treated as Auto.

[timunie]

Try to not set SharedGridSizeGroup to a column with size *. Then it works for me.