Originally Posted by
ImageGear
Quick note:
It should be remembered that PDF's are capable of being annotated with an overlay which might be a small box or text wihout redrawing the entire diagram.
In this case the issue appears to be a missing font, as described by MarcK on the previous page. I'd agree with your underlying point that not all pdfs are created (or edited) equal. I would have thought that modifying these charts would be done in a regimented way, but apparently not...