Final answer:
In a digital audio workstation's piano roll editor, using Alt left click on a note and dragging a. duplicates the selected notes, which is a common technique in music composition.
Step-by-step explanation:
The question is related to the use of a specific functionality within a digital audio workstation (DAW), which is typically used for music production. When using the piano roll editor in a DAW, pressing Alt left click on a piano roll note and a. dragging performs the action of duplicating selected notes.
This is a common technique for quickly copying musical phrases or motifs within a composition. The statement "Every good boy does fine" is indeed a mnemonic to help remember the notes E, G, B, D, and F for the lines of the treble clef, which is useful when learning to read music for piano or other treble clef instruments.