'''bold text'''I am working with an html document located on my desktop (so no internet access involved). There are links to movies which work fine. There are links to a pdf document which don't work and just open an empty tab. My understanding of the relationship between Firefox and the plug-ins / add-ons in minimal so I don't know where the problem lies. The document is an established piece of educational software with many hundreds of users having not experienced this problem which suggests the files are set up correctly. I've tried adjusting the setting of pdf download (under Firefox/Tools) but they seem to make no difference as though that's not the plug-in being called for.