Help Me Figure Out Gmail Popup

I've set up Gmail to pop up a notification when new email arrives. And it does, at the lower right screen corner, like most all Win 10 notifications. Clicking the pop up (or tapping in my case since I use a touch screen 2-in-1 laptop) brings up GMail webpage on my Firefox browser, but it's completely blank! I always have to do a refresh (reload) to see the normal page (inbox with listing of emails). Alternatively, I leave the pop up alone and just navigate my browser to Gmail webpage, to avoid the blank page - reload routine.

Any idea why clicking/tapping popup notification "blanks out" Gmail webpage??

Details: Dell XPS, Win 10, Firefox - with Google and Gmail pop up's specifically allowed. This has been going on for a few years so I doubt the Win or Firefox versions are the problem.

 

I use both Gmail and Firefox too but much prefer to use an email client rather than webmail. Maybe that would be your best solution.