How to Select an Entire Clip with One Click

"Gah!", I said. "Why can't I select an entire clip by clicking on it?"

"Double-click? No."

"Double-click really fast? No."

"GAH!"

Well, I was right. I couldn't select an entire clip with one click...yet.
Luckily, the iLife UI engineers weren't out to lunch on this one. If you go to the iMovie preferences, you will find a setting to make the necessary change.

The default for this setting is to select four seconds of video with each click. Notice that the timing for that setting is adjustable. You can also set it so that your clicks will deselect everything. (You would use this if you only want to select clips by dragging.) I like selecting an entire clip with one click because it seems the most intuitive to me. Glad to have that sorted out.