[FF] Extension window displaying at half width w/o horizontal scrolling

FireFox version 73.0.1, but has been persisting for multiple version.

This issue occurs both on my Desktop and Laptop.
Most of the functionality is there, the autofill for example works, but there are certain issues:
Since the horizontal scrolling is not functional, I can not access the right half of the window, e.g. to add a new Log-In.

Provided below are imgur links with example screenshots.
https://i.imgur.com/ezjWy43.png
As can be seen in the following picture, manipulating the slide bar to the right did not move the window:
https://i.imgur.com/4io7IMd.png

I have recently changed my account type to family account, and am in the process of setting up multiple family members with 1PW.
Most of them also use FF, and for them the window displays as expected on all devices I have seen them use. I have already tried to see if other browser extensions interfer, but non of my fiddlings have yielded results. A fresh FF installation also did nothing, although I did not perform a clean install as at the moment I am wary of losing some data.

So yeah, a pretty exotic issue, but it finally needled my enough to give solving it a proper shot.

1Password Version: 7.3.12
Extension Version: 1.18.0 - updated Feb 21st
OS Version: Win10
Sync Type: Not Provided