Oh, that might actually be it. The 'download file' button in the pdf.js menu is a different button from the button at the bottom/right hand side of the page (wi

Oh, that might actually be it. The 'download file' button in the pdf.js menu is a different button from the button at the bottom/right hand side of the page (with different code behind it - the pdf.js 'download' button comes stock with pdf.js). I haven't really tested its behaviour much, but it's quite possible that it's calling things document.pdf. Perhaps I should just remove the pdf.js 'download' button, seeing as there's one elsewhere in the UI anyway.