When Apple upgraded Final Cut from FCP 7 to Final Cut X, there were a number of features that were not offered in the new version.
One of those was Chapter Markers for DVDs.
UpDate November 2012:
However – Since the FCP X update 10.0.6, Chapter Marker creation has now been added to FCP. But this process with the 3rd party App – Metadata Hootenanny – is still useful if you have forgotten to add Chapter markers prior to export from FCP or need to move or add extra Chapter Markers. This means that you do not need to open your project in FCP X again.
Apple have long said that the DVD is dead, but in the real world we are still asked for DVDs and Chapter Markers are a necessary part of the DVD creation procedure.
Here is a simple way to add Chapter Markers to exported clips from FCP X or even delete or move previously added Chapter markers from FCP 7 clips.
The Donationware application is: