It’s worded a bit confusingly, but:
- The brighter LED indicates that, on the last step, the note will be held for the full step.
- The dim LED indicates that, on the last step, the note will be held only for the duration specified by “length” in the bar menu.
If you have a chord on step 1 and a chord on step 5, you can make the chords slightly overlap by setting step 1’s duration to 5 steps, pressing the 5th step again for the dim LED.
Then go to Bar, set Scale to 8 and length to 25–now you should hear the chords briefly overlap.
If you hold step 1 and press step 5 again, bringing back the bright LED, you’ll hear the chords overlap for much longer.
There won’t be a difference if Length is set to 100.