Unable to attach files to secure notes, passport, driver's license, etc. Windows with Chrome browser

Thank you Ekalb, that solves one mystery, though I still don't understand how I could have a signed up, imported passwords, and used the browser version of 1P without ever downloading the program. It seems like that download would have happened during the sign up process.
Regardless, having 1P v8 installed has not solved my problem of being unable to attach files to items. For example, I have a passport item with all my passport information entered as text. I'd like to attach an image of the passport. Now, with 1P v8 installed, when I go to edit the + button remains in view but is grayed out and non-functional. Thoughts?