If you find that the popup doesn't show up automatically anymore when you download a PDF online then follow the below steps:
On the top right of Chrome, click on the three dots and choose settings.
Click on Downloads.
Where it says Open certain file types automatically after downloading, click on clear.
Go back to the website and click on download again, when the PDF has downloaded, right-click it and choose Always open files of this type.
Refresh the page and download again to check that it then shows up the window for you to open it straight after downloading.
This should now work when you download a pdf, this can be done for any other file type you download.
If you’re still having issues then please raise a new case online and reference the title of this article.