textDescription.addVerifyListener(new VerifyListener() {
      @Override
      public void verifyText(VerifyEvent event) {
        if (event.doit == false) {
          // event already consumed
          return;
        }
        if (textDescription.getText().length() > DESC_LENGTH) {
          // show the field decorator
          dec.show();
          event.doit = false;
          if (event.character == '\u0008' || event.character == '\u007F') {
            // allow delete and/or backspace to be processed
            event.doit = true;
          }
        } else {
          // hide the field decorator
          dec.hide();
        }
      }
    });

    textDescription.addPaintListener(new PaintListener() {
      public void paintControl(PaintEvent evt) {
        Point s = textDescription.getSize();
        Color c = evt.gc.getForeground();
        evt.gc.setForeground(textDescription.getDisplay().getSystemColor(
            SWT.COLOR_RED));
        evt.gc.drawRectangle(0, 0, s.x - 5, s.y - 5);
        evt.gc.setForeground(c);
      }
    });