RoundingDecimalPlace value for DataGridDoubleColumn is not specified.

I wanted to pass a null value to the RoundingDecimalPlace of the DoubleEditBox in ThemedDataGrid and wrote the following code, but the null is not set correctly.

<datagrid:ThemedDataGrid>
  <datagrid:ThemedDataGrid.Columns>
    <datagrideditors:DataGridDoubleColumn RoundingDecimalPlace="{x:Null}"/>
  </datagrid:ThemedDataGrid.Columns>
</datagrid:ThemedDataGrid>

Expected: RoundingDecimalPlace is null

Actual: RoundingDecimalPlace is 8

https://imgur.com/a/ZVeew6K

Steps to Reproduce:

1. Create new WPF project
2. Edit the code as follows

   *.csproj

   <Project Sdk="Microsoft.NET.Sdk">
     <PropertyGroup>
       <OutputType>WinExe</OutputType>
       <TargetFramework>net5.0-windows</TargetFramework>
       <Nullable>enable</Nullable>
       <UseWPF>true</UseWPF>
     </PropertyGroup>
   
     <ItemGroup>
       <PackageReference Include="ActiproSoftware.Controls.WPF.Editors.Interop.DataGrid" Version="21.1.3" />
       <PackageReference Include="ActiproSoftware.Controls.WPF.DataGrid.Contrib" Version="21.1.3" />
     </ItemGroup>
   </Project>
   

   MainWindow.xaml

   <Window x:Class="WpfApp31.MainWindow"
           xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
           xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
           xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
           xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
           xmlns:datagrid="http://schemas.actiprosoftware.com/winfx/xaml/datagrid"
           xmlns:datagrideditors="http://schemas.actiprosoftware.com/winfx/xaml/datagrideditors"
           mc:Ignorable="d"
           Title="MainWindow" Height="450" Width="800">
       
       <datagrid:ThemedDataGrid AutoGenerateColumns="False" ItemsSource="{Binding}">
           <datagrid:ThemedDataGrid.Columns>
               <datagrideditors:DataGridDoubleColumn
                   Width="*"
                   Format="G"
                   Header="Value"
                   RoundingDecimalPlace="{x:Null}"
                   Binding="{Binding Value}"/>
           </datagrid:ThemedDataGrid.Columns>
       </datagrid:ThemedDataGrid>
   </Window>
   

   MainWindow.xaml.cs

   namespace WpfApp31
   {
       public partial class MainWindow : Window
       {
           public MainWindow()
           {
               InitializeComponent();
               this.DataContext = new Data[] { new(0), new(1) };
           }
       }
   
       public record Data(double Value);
   }

3. Build and run