Force Touch trackpad gestures in iMovie on Mac
If you have a Force Touch trackpad, you can access additional functions in iMovie by changing how hard you press. The trackpad also gives you feedback (you feel a subtle vibration) when you:
Drag the crop rectangle and it snaps to an alignment guide when cropping
Drag past the end or beginning of a clip in the timeline
Drag a title on top of a clip in the timeline
Fast-forward and rewind clips
In the iMovie app 
on your Mac, do any of the following:
Fast-forward: Click and hold the Next button
below the viewer; press harder to increase the speed.Rewind: Click and hold the Previous button
below the viewer; press harder to increase the speed.
Change the animated travel map type
You can change the type of animated travel map you’re using in a movie without leaving the timeline.
In the iMovie app
on your Mac, force click a background map in the timeline (press firmly until you feel a deeper click), and choose a map style from the menu.