Changing the length of a pattern in the Pattern editor allows you to add a pause behind the last MIDI event of the pattern, for example.
Procedure
Drag the end marker to a new position on the timeline.
If you drag the end marker to the left and the bars behind the end marker are empty, the length of the pattern is shortened automatically.
If you drag the end marker to the left and the bars behind the end marker contain MIDI events, the length of the pattern is shortened only to the bar that contains the last MIDI event. No MIDI events are deleted.