Clear Selected Ranges In FCPX

You can remove one or more ranges from the browser or the timeline.

Clear one or more ranges in the browser or the timeline: Select the range or ranges, then choose Mark > Clear Selected Ranges (or press Option-X)

Remove all ranges in an event: Choose Edit > Select All (or press Command-A) to select all ranges in the current event, then choose Mark > Clear Selected Ranges (or press Option-X).