private void TextBox_PreviewKeyDown(object sender, KeyEventArgs e)
 {
     if (mainClass == null)
     {
         mainClass = new frmMain();
     }
     mainClass.CallShortcutKeys(e, IsAlredyCallProperty);
     IsAlredyCallProperty = true;
 }
        //
        private void BraileBox_PreviewKeyDown(object sender, KeyEventArgs e)
        {
            if (mainClass == null)
            {
                mainClass = new frmMain();
            }
            mainClass.CallShortcutKeys(e, IsAlredyCallProperty);
            IsAlredyCallProperty = true;

            //F2 key edit selection in braille code
            if (e.Key == Key.F2 && !String.IsNullOrEmpty(BraileBox.Selection.Text))
            {
                int startIndex = this.BraileBox.Document.ContentStart.GetOffsetToPosition(this.BraileBox.Selection.Start);
                int endIndex = this.BraileBox.Document.ContentStart.GetOffsetToPosition(this.BraileBox.Selection.End);

                TextPointer startTextPointer = this.TextBox.Document.ContentStart.GetPositionAtOffset(startIndex);
                TextPointer endTextPointer = this.TextBox.Document.ContentStart.GetPositionAtOffset(endIndex);

                TextBox.Selection.Select(startTextPointer, endTextPointer);
                TextBox.Focus();
            }
        }