One of the many delightful surprises in the latest version of Aperture is tabbed browsing. That’s right, you can have multiple albums, projects, web galleries, etc. open at once, then switch among them just like you can with multiple web pages in Safari.
To create a new tab, just hold down the CMD key when clicking on a new collection (such as an album). Aperture will create the new workspace and display the thumbnails. You can switch back and forth among tabs by merely clicking on their labels.
This is very handy when you’re working on projects and need to quickly toggle among several albums without searching for them in your Projects pane.