One of my favourite new commands in Mavericks is Finder’s ‘Merge All Windows’. You can find this in the Finder’s menu bar Window menu, but note that it’ll be greyed out if you only have one Finder window open (one of my other new favourites is
⌘ ^ space. Try it in Text Edit or Safari’s search bar, but I digress…:p).
To see ‘Merge All Windows’ in action, open up two or more Finder windows. Throw one or two on different Desktop spaces for good measure, then hit the ‘Merge All Windows’ command.
Yes, you get all your open windows from wherever they’re distributed slamdunked into one window with multiple tabs. If, like me, you work across multiple monitors and have multiple desktop spaces on each, Finder windows can rapidly start to multiply and this command is a real boon.
In fact, I like the ‘Merge All Windows’ command so much I even made a shortcut for it in System Preferences > Keyboard > Shortcuts (see the screenshot at the top of the page)
One final trick while we’re on the subject of tabs in Finder windows, note that you can open any folder item in your Sidebar into a new tab automatically by holding down the ⌘ ‘Command’ key and clicking on the Sidebar folder item.