Legato
Extends each selected note so that it reaches the next note.
You can specify a gap or overlap for this function with the “Legato Overlap” setting in the Preferences dialog (Editing–MIDI page).
When you activate “Legato Mode: Between Selected Notes Only”, the length of the note will be adjusted so that it reaches the next selected note, allowing you to apply Legato only to your bass line, for example.
Note
You can also apply a legato using the “Scale Length/Legato” slider in the MIDI editors.