Cannot fully hide middle row when bottom row has data

I'm pretty new to Xamarin so I may be missing something simple, but I cannot for the life of me get a layout going in a ListView which can dynamically adjust the vertical height of the element when some bound elements are missing.

Here's the XAML...

    <ContentPage.Content>
        <StackLayout>
            <ListView ItemsSource="{Binding Items}" HasUnevenRows="True">
                <ListView.ItemTemplate>
                    <DataTemplate>
                        <ViewCell>
                            <Grid Padding="0">
                                <Grid.RowDefinitions>
                                    <RowDefinition Height="22"></RowDefinition>
                                    <RowDefinition Height="{Binding PriceHeight}"></RowDefinition>
                                    <RowDefinition Height="{Binding ShortDescriptionHeight}"></RowDefinition>
                                </Grid.RowDefinitions>
                                <Grid.ColumnDefinitions>
                                    <ColumnDefinition Width="*"></ColumnDefinition>
                                    <ColumnDefinition Width="80"></ColumnDefinition>
                                </Grid.ColumnDefinitions>

                                <Label Grid.Row="0" Grid.Column="0" Text="{Binding Everything}" Font="Large" LineBreakMode="TailTruncation" />
                                <Label Grid.Row="1" Grid.Column="0" Text="{Binding Price}" IsVisible="{Binding HasPrice}" Font="Large" />
                                <Label Grid.Row="2" Grid.Column="0" Text="{Binding ShortDescription}" IsVisible="{Binding HasShortDescription}" Font="Medium" TextColor="Gray" LineBreakMode="WordWrap" />
                            </Grid>
                        </ViewCell>
                    </DataTemplate>
                </ListView.ItemTemplate>
            </ListView>
        </StackLayout>
    </ContentPage.Content>

When PriceHeight = 0 and HasPrice = False and ShortDescriptionHeight = 0 and HasShortDescription = False I'm getting exactly what I expect. My list item is short and just displays the data from Everything. But if PriceHeight = 0 and HasPrice = False and ShortDescriptionHeight = 10 and HasShortDescription = True... it allocates a big glob of empty whitespace for row 1 between Everything and ShortDescription.

I'm clearly missing something. Who can help me with what that something is?