private String getCollapsedText(ITextRegion region) {
   if (fParentRegion == null) return ""; // $NON-NLS-1$
   StringBuffer text = new StringBuffer(fParentRegion.getFullText(region));
   if (region.getLength() > region.getTextLength())
     text.replace(region.getTextLength(), region.getLength(), " "); // $NON-NLS-1$
   return text.toString();
 }