How to expand the auto hide tab programmatically in WPF DockingManager?

<StackPanel Height="30" Orientation="Horizontal">
  <!--TextBox-->
  <TextBlock Margin="5" Text="Type open to start the autohide animation :  " />
  <TextBox Name="Txtbox" Width="100" Margin="5" HorizontalAlignment="Center" VerticalAlignment="Top" HorizontalContentAlignment="Center" VerticalContentAlignment="Center" Text="">
    <i:Interaction.Triggers>
    <!-- Command Binding -->
      <i:EventTrigger EventName="TextChanged">
        <i:InvokeCommandAction Command="{Binding OpenCommand}" />
      </i:EventTrigger>
    </i:Interaction.Triggers>
  </TextBox>
</StackPanel>
 
<syncfusion:DockingManager Grid.Row="1" Name="Docking">
  <ContentControl Name="MyTab" syncfusion:DockingManager.DesiredHeightInDockedMode="200" syncfusion:DockingManager.Header="Messages" syncfusion:DockingManager.SideInDockedMode="Left" syncfusion:DockingManager.State="AutoHidden" />
</syncfusion:DockingManager>

/// <summary>
/// Open Command
/// </summary>
private ICommand _opencommand;
/// <summary>
/// Command to Open the Auto Hidden Window
/// </summary>
public ICommand OpenCommand
{
 get
 {
  return _opencommand ?? (_opencommand = new CommandHandler(() => MyAction(), true));
 }
}
 
/// <summary>
/// Perform action to open Auto Hidden Window
/// </summary>
private void MyAction()
{
 MainHost host = VisualUtils.FindDescendant(Docking, typeof(MainHost)) as MainHost;
 if (host != null)
 {
   SidePanel leftpanel = host.Template.FindName("PART_LeftPanel", host) as SidePanel;
   SidePanel RightPanel = host.Template.FindName("PART_RightPanel", host) as SidePanel;
   SidePanel BottomPanel = host.Template.FindName("PART_BottomPanel", host) as SidePanel;
   SidePanel TopPanel = host.Template.FindName("PART_TopPanel", host) as SidePanel;
 
   // Call to open the Autohidden Tab
   if (leftpanel.TabChildren.Contains(MyTab))
     leftpanel.SelectTab(MyTab);
   else if (RightPanel.TabChildren.Contains(MyTab))
     RightPanel.SelectTab(MyTab);
   else if (BottomPanel.TabChildren.Contains(MyTab))
     BottomPanel.SelectTab(MyTab);
   else if (TopPanel.TabChildren.Contains(MyTab))
     TopPanel.SelectTab(MyTab);
  }
}