I wasn't about to go off on one don't worry! Just expressing that I feel unqualified(!) every time I can't work my own way out of a problem. Anyway, am just figuring out how to do what you suggest on dropbox..
@YSal: OK, I found the screenshot in the earlier version of your post. So it looks like the item pane is collapsed there. If you go to the View menu → Layout, is Item Pane checked or unchecked?
https://www.zotero.org/support/forum_guidelines#etiquette
Take a screenshot that shows the problem, upload it somewhere (e.g., Dropbox), and post the link here.