Keys · Enter new · Tab/⇧Tab nest · ⌫ merge · ⌘⇧⌫ delete · click a bullet to zoom (⇧click new tab, ⌘click new pane), drag across panes/tabs · Esc zoom out · ⌘↵ complete · ⌘1–9 tabs · ⌘Z undo · / or drop a file to attach