What kind of computer is this? What graphics card is this? Is this on an external monitor or a laptop screen?
This would be something related to your graphics drivers. You should make sure you're running the latest drivers.
If this is Nvidia, and you go into the Nvidia control panel, there may also some application specific options there for Firefox and Zotero. You should see if you can copy the Firefox settings for Zotero and whether that solves the issue.
But if I drag this window to the other monitor, then it displays normally.
What kind of computer is this? What graphics card is this? Is this on an external monitor or a laptop screen?
This would be something related to your graphics drivers. You should make sure you're running the latest drivers.
If this is Nvidia, and you go into the Nvidia control panel, there may also some application specific options there for Firefox and Zotero. You should see if you can copy the Firefox settings for Zotero and whether that solves the issue.