Sustain

Sustain is the ability to hold out a note to it's full extent. For example, the violin sample has the ability to hold out its note for a considerable length of time.

Certain instruments like the 8bit instruments have the ability to sustain their notes longer than samples due to the sounds being generated by oscillators built into the Web Audio API that online sequencer uses.

to create a sustained note, you must drag out the note on the right side. Conversly, you can also drag notes smaller and have a small release on the instrument.

Note: you cannot do this with all instruments. Please refer to https://onlinesequencer.net/wiki/Pseudosustain for more details on sustaining non sustained instruments.