I can't see changes in datagrid

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WPF

Hi, hello to all that help. I'm learning WPF and making small testing, I am changing the value of a cell at the moment when I am editing another cell of the same row. The change in the cell is made, but the change in the datagrid is not observed.

What am I omitting so that the value that I am modifying is updated?

Thanks for the help.
I know that is about something textbox cell.
Please, help me to identify my mistake. Thanks a lot,

What I have tried:

This is my code(reduced):

public class clEmployee
{
   public int employeeID { get; set; }
   public string employeeNam { get; set; }
   public Boolean isChanged { get; set; }
}

<datagrid
    x:name="dgTesting"
	margin="5,5,10,5"
	autogeneratecolumns="False" 
	horizontalalignment="Stretch"
	itemssource="{Binding myEmployees}"
	verticalalignment="Stretch"
	currentcellchanged="dgTesting_CurrentCellChanged"
	celleditending="dgTesting_CellEditEnding"
	previewkeydown="dgTesting_PreviewKeyDown"
	height="500"
	grid.column="0"
	grid.row="1">
          <datagrid.columns>
                <datagridtextcolumn binding="{Binding Path=employeeID, Mode=TwoWay}" header="ID">
                <datagridtextcolumn binding="{Binding Path=employeeName, Mode=TwoWay}" header="Names" width="700">
                <datagridtextcolumn binding="{Binding Path=isChanged, Mode=TwoWay}" header="Changes">

public partial class wCatEmployees : Window
{
	ObservableCollection<clemployee> myEmployees= new ObservableCollection<clemployee>();

	public wCatEmployees()
	{
		InitializeComponent();
		loadEployees();
	}

	private void loadEployees()
	{
		myEmployees = a.LoadEmployees();
		dgTesting.ItemsSource = myEmployees;
	}

	private void dgTesting_PreviewKeyDown(object sender, KeyEventArgs e)
	{
		if (e.Key == Key.Enter || e.Key == Key.Return)
		{
			e.Handled = true;
			dgTesting.CommitEdit();
		}
	}
	
	private void dgTesting_CellEditEnding(object sender, DataGridCellEditEndingEventArgs e)
	{
		if (e.EditAction != DataGridEditAction.Commit) { return; }
			if (e.Column.SortMemberPath.Equals("employeeName"))
		{
			
			int Fi = dgTesting.Items.IndexOf(dgTesting.CurrentItem);
			((clEmployee)dgTesting.Items[Fi]).isChanged = true; // <====Here, I don't see the change in the datagrid

			this.dgTesting.Items.Refresh(); // <=====  If I do that an exception ocurrs
		}
	}
}

I don't know what more else to do.