If you do not intend to update the folder you are opening, you should choose this option. Updating folders When you update a folder, changes you've made to it become permanent. Files that are marked for deletion are removed permanently. Files that have been saved to other folders are also deleted from the active folder when you update it. To update a folder, push the Update button at the bottom of the window, choose Update from the Folder pulldown menu or click on the update icon in the toolbar.
Closing folders Open folders consume system resources.
If you're finished working with a folder, it's a good idea to close it. When the folder is active, choose Close from the Folder pulldown menu to close it. Choose this item to quickly re-open closed folders. If you select a directory that is not empty, a dialog appears so you may confirm the action. If you click Yes, the directory and its contents are removed.