TAB navigation does not work properly with Grid TimePickerCell. The timepicker cell gets the focus only for a moment, and the grid immediately sets the focus to the next cell.

 public Form1()
 {
            radGridView1.Columns.Add(new GridViewDateTimeColumn());
            radGridView1.EditorRequired += new EditorRequiredEventHandler(radGridView1_EditorRequired);
    
 }

 void radGridView1_EditorRequired(object sender, EditorRequiredEventArgs e)
 {
      e.Editor = new GridTimePickerEditor();
  }