Dynamic add and remove item in Property

<p>I faced with next: if I add or remove item to/from PropertyGrid.ItemsSource (using ItemsSource.Remove() /   ItemsSource.Add() methods  ) , then PropertyGrid re-create. Why   is  it  a problem? I just wrap property groups in expander (see below) and arter this re-creation Expander.IsExpanded set to default value.</p>

<p>Can this behavior be changed?</p>

<p>

<GroupStyle>
<GroupStyle.ContainerStyle>
<Style TargetType="{x:Type GroupItem}">
<Setter Property="Template">
<Setter.Value>
<ControlTemplate>
<Border Name="Bd" BorderBrush="Gray" BorderThickness="1.5"
CornerRadius="3" Margin="20,8,20,8"
RenderTransformOrigin="0.5,0.5">
<StackPanel>
<Expander IsExpanded="True" Background="Transparent" Padding="3,3,3,7" Header="{Binding Name}">
<Border Name="TitleBd" BorderBrush="DarkGray" BorderThickness="2" CornerRadius="3">
<ItemsPresenter />
</Border>
</Expander>


</StackPanel>
<Border.RenderTransform>
<TransformGroup>
<ScaleTransform x:Name="GroupScaler" ScaleX="1" ScaleY="1" />
</TransformGroup>
</Border.RenderTransform>
</Border>

</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
</GroupStyle.ContainerStyle>
</GroupStyle>

</p>

I need to remove and then to add because I want to change type of property on the fly