// Serialize and read again
ByteArrayOutputStream out = new ByteArrayOutputStream();
ppt.write(out);
out.close();
ppt = new SlideShow(new HSLFSlideShow(new ByteArrayInputStream(out.toByteArray())));
sl = ppt.getSlides()[0];
txtbox = (TextBox)sl.getShapes()[0];
rt = txtbox.getTextRun().getRichTextRuns()[0];