Content inject in a pdf page

[antoni4040]

Hello. Thank you for this wonderful framework, makes everything much easier.
I have a question and maybe there is no solution, but that's ok. I'm building an extension and I would like to try and make it work with pdfs opened in the browser. The problem is that it fails to inject content.js in pdf pages saying
Error activating content script: Error: No tab with id: -1
Is there a workaround, a permission missing or something? Thank you!