SI-24, Studio Package Pro, SPP: Deleting a marker?
To delete a MARKER:
1- Press the MARKER button,
2- Press the - button for the marker to delete.
3- Hold SHIFT and press the  button to delete.
The markers are stored on - in the order of playback. This means that if you assign a new marker or delete a marker, the position may change to a different number - to keep the current order of playback in the form of a timeline.