When FCP X was released it was missing
the ability to retain in and out points
“in” & “out” points were not retained in the browser raw footage clips after they were edited into the time line.
To date FCP X still does not retain the “in” & “out” points, but a work-around can be used to create sub clips by using the keyword organisation feature of FCP X.
The video below shows how:
(Of course you can use the “favorites” feature, which will remember that portion of the clip. Just select the part of the clip you want to remember and press the “f” key –
Also from the edited clip in the timeline you can select: “show in event browser” which highlights, in the event browser, the” in” and “out” points that were used in that clip.)