Create Lane Set
Creates a lane set so you can focus on certain MIDI events out of the many possible.
Use Lane Sets in the Step Editor in Logic Pro — Apple Support
The Lane Set functions let you limit the Step Editor display to only the required MIDI event types. For example, imagine you have recorded a synthesizer lead MIDI region. You could create a Lane Set that contains individual lanes for each note pitch in the region. Drag each note event step vertically to adjust its level. Within the same Lane Set, you could create two more lanes to control the lead synthesizer’s filter cutoff and resonance parameters, allowing you to create or precisely edit filter changes.
Logic Pro Step Editor Overview — Apple Support
The Step Editor is a graphical editor that can be used to create or edit MIDI note and controller data. You can use the Step Editor to view and edit different MIDI event types, shown as vertical beams—or steps—along a timeline within a region.