Apple Logic Pro 9 - Manual (Page 664)

2 Click the Editing tab, then select the Limit Dragging to One Direction in Piano Roll and
Score checkbox.
When active, this option helps you to avoid accidental transpositions of notes when
moving them horizontally, or changing the position of notes when you’re trying to change
their pitch. The initial movement—vertical or horizontal—restricts further movements
to this plane, while the mouse button is held. Release the mouse button and click the
event to move in the other direction.
Moving Events via Key Commands
Editing can be greatly accelerated by assigning, and using, the following key commands
to move one or more events.
• Nudge Region/Event Position Right by SMPTE Frame
• Nudge Region/Event Position Left by SMPTE Frame
• Nudge Region/Event Position Right by 1/2 SMPTE Frame
• Nudge Region/Event Position Left by 1/2 SMPTE Frame
• Nudge Region/Event Position Right by 5 SMPTE Frames
• Nudge Region/Event Position Left by 5 SMPTE Frames
• Nudge Region/Event Position Right by SMPTE Bit
• Nudge Region/Event Position Left by SMPTE Bit
• Nudge Region/Event Position Right by Tick
• Nudge Region/Event Position Left by Tick
• Nudge Region/Event Position Right by Division
• Nudge Region/Event Position Left by Division
• Nudge Region/Event Position Right by Beat
• Nudge Region/Event Position Left by Beat
• Nudge Region/Event Position Right by Bar
664 Chapter 23 Editing MIDI Events in the Piano Roll Editor