And the first hint is…

Add a recent documents stack item to your dock for quick access to all your recent documents.Recent Docs StackOpen Terminal and type: defaults write com.apple.dock persistent-others -array-add '{ "tile-data" = { "list-type" = 1; }; "tile-type" = "recents-tile"; }'After that, type: killall Dock in terminal to restart the dock.Finally, control click on the new folder and choose “Recent Documents.”You can set the number of documents remembered in System Preferences, Appearance.via: macosxhints.com