Upgrade Storagehere is an easy one
If all my files become open in a collection, that is, the little arrow next the the title is pointing down showing the PDF or text (whatever).
Then how can I close them all at once?
Then how can I close them all at once?
To close all open items in Zotero, select any item and press the minus (-) key on your keyboard to collapse all items in a collection view. You can also use the plus (+) key to expand all items if needed.