See http://code.google.com/p/sumatrapdf/issues/detail?id=1044 for a document containing an annotation that's supposed to be rendered only on mouse-hover. I'd expect a non-interactive PDF renderer to ignore these annotations. Our patch: http://code.google.com/p/sumatrapdf/source/detail?r=2156 See "12.5.3 Annotation Flags" in the PDF 1.7 spec for the flag values.