Is there a way to collapse all the actors in the outliner at once. When I duplicate multiple actors, they all expand and it makes it hard to see the actors in the outliner. If not, can this be a feature request?
Never mind, I found it 
right click any folder actor → Collapse All works on folders, but for loose actors shift+click the arrow on parent once collapses children recursively.
also in outliner settings enable Sort by Type then select all duplicatd actors, right click → Move To → New Folder and collapse that folder. not ideal but saves scrolling until Epic adds a real Collapse All button.