In manual of the TeX package "fontspec", available at http://ftp.ctan.org/tex-archive/macros/xetex/latex/fontspec/fontspec.pdf, some parts of the text are not visible both when the PDF file is displayed directly in evince, or when it is converted to PostScript using "pdftops" and displayed in evince as PostScript.

The letters are missing not only as glyphs, but I also cannot select them in evince using mouse: when I select e.g. the whole paragraph and paste it to the different window, only the letters which were actually displayed are pasted.

When converted to PostScript using "pdf2ps" rather than "pdftops", all the letters in the document are displayed correctly. So I guess it is a bug in poppler rather than evince.

The letters which are not displayed are all letters from the code examples (the monospace font). Example: the third page (numbered "2", section "1. Introduction") - the contents of the parenthesis in the first paragraph is missing except commas, and the code example in "1.1 Usage" is missing altogether.
I can attach screenshots if requested.

My system is Fedora 12, x86_64, with the following poppler version:

poppler-0.12.2-1.fc12.x86_64
poppler-utils-0.12.2-1.fc12.x86_64