iMovie menu items unavailable
I have exported some movies taken on an iPhone 6 in iOS 8.3 from my Mac Mini's Photos app to the Movies folder, then added them as clips to a project in iMovie on the Mini.
But when trying to edit, most of the basic menu functions like Trim to Selection, Detach Audio, Clip Trimmer, Join Clips, etc. are grayed out! How can I get these enabled?
OS 10.10.4, iMovie 10.0.9, both updated yesterday.
Mac mini, OS X Yosemite (10.10.4)