Qt Assistant PDF display? (Collection file containing PDF document.)

[toralf]

I have a help collection file that contains a PDF document, with a link to it from one of the HTML pages. What is supposed to happen when I click on the PDF link in Qt assistant? On my set-up, it looks like assistant thinks it is able to display the document in-line, but it isn't really. Instead, it appears to handle the data as it it were a plain text document - it shows me "garbled" content starting with

%PDF-1.5 %µí®û 3 0 obj > stream xœíɊÉõ_‘gC§b_èƒÁŸlø0øÐÊVÏJƒgùü¶Ø2³ª»J

I get this with version 5.9.2 and 4.8.7 (Qt 5 and Qt 4 releases supplied with CentOS 7), but I think I've seen something similar with other versions in the past.

So, what's going on here? Is this a bug, or is there a plugin or something that's missing? Can I tell assistant not to try to display the document directly, but instead pass it to an external tool?

Thanks.

- Toralf