Font in Zotero half screen is huge...
but normal when in full screen mode. Using FF4 and Zotero 2.1.1. I have small font size selected in preferences. Hard to do metadata with the larger font that appears because yoyu cannot see the fields on the screen.
Also try going to about:config and searching for "extensions.zotero.fontSize" -- you can set it to something like "0.7" to get a more reasonable size for metadata (I think this option should be in the main preferences-- Zotero is nearly unusable with the default size!)