Empty inline pdf

[eluser]Geoffrey[/eluser]
It doesn't appear to be a tcpdf issue as the problem exists in another codeigniter project I've done that uses fpdf. This second project is using CI 1.6.3 rather than 1.7.0 when I first encountered the issue.

Looking at the database where I am storing the session data, it seems that when Acrobat loads the pdf, a new session id is being generated in the Db with no user_data and as such, the pdf is empty. The original session is still there with the user_data I need but I can't get to it.

How do I stop a new session being initiated and get it to use the existing session?