✅ WPF MouseOver expansion of item isn't working

                <Grid
                    x:Name="gridExtended"
                    DockPanel.Dock="Bottom"
                    IsMouseDirectlyOverChanged="OnExtendedToolBarMouseDirectlyOverChanged">
                    <Grid.RowDefinitions>
                        <RowDefinition
                            Height="10" />
                        <RowDefinition
                            Height="{Binding ExtendedToolBarRowTwoHeight, ElementName=window, NotifyOnSourceUpdated=True, NotifyOnTargetUpdated=True}" />
                    </Grid.RowDefinitions>
                    <Separator
                        VerticalContentAlignment="Center"
                        HorizontalContentAlignment="Stretch"
                        Grid.ColumnSpan="25"
                        Height="1" />

        public System.Windows.GridLength ExtendedToolBarRowTwoHeight
        {
            get
            {
                if(gridExtended == null || chkExtendedToolBarShow == null)
                    System.Diagnostics.Debug.WriteLine("Nulls");
                else
                    System.Diagnostics.Debug.WriteLine($"Extended: {gridExtended.IsMouseDirectlyOver
                        }\tCheckbox: {chkExtendedToolBarShow.IsChecked}");
                return gridExtended != null && chkExtendedToolBarShow != null && (gridExtended.IsMouseDirectlyOver
                    || chkExtendedToolBarShow.IsChecked == true) ? System.Windows.GridLength.Auto : new
                    (0);
            }
        }