There's a sticky thread that says 1PasswordX shows a "blank page" in Firefox private browsing mode with certain settings. Assuming "blank page" means the popup is a white square, I'm experiencing that as well.
The sticky says it can be caused by either of these settings:
Never remember history
Always use private browsing mode
But my browser doesn't have those enabled. My "History" settings are as follows:
Firefox will Use custom settings for history
[OFF] Always use private browsing mode
[ON] Remember browsing and download history
[OFF] Remember search and form history
[OFF] Clear history when Firefox closes
The "Content blocking" settings are set to the default that the browser ships with: "Standard - Only blocks known trackers in Private Windows"
I think it's worth noting that the extension still works (the 1P icon appears in text boxes and I can still fill forms from there, but the popup won't show).
Let me know if you need any more info to diagnose this issue. I'd love to get it resolved soon; it's become a hassle to log into various hub-type websites, lol.
1Password Version: 7.3.657, but it's not even running
Extension Version: 1Password X 1.13.2
OS Version: Windows 10
Sync Type: Not Provided