Select All Regions and Events

Located in the Edit menu — ‘Select All Regions and Events’. I am not quite sure where this would come in to use, but I certainly understand the concept.

Selects all of the regions and events for the currently “in use” tracks in the Main Window Tracks, as well as everything currently visible in the Score Editor window.

Logic Pro music notation overview — Apple Support

You can view MIDI regions in software instrument (and external MIDI instrument) tracks as music notation in the Score Editor. Notes and other musical events are displayed as standard notation, along with common symbols such as time and key signature, bar lines, and clef signs. You can add and edit notes, add sustain pedal markings and other symbols, and print the score.

Select multiple regions in the Logic Pro Score Editor — Apple Support

Click an instrument name in the column between the parameters and score, to select all regions for that track (including regions on different tracks that are assigned to the same software instrument channel), at the current display level.