Apple Logic Pro 9 - Manual (Page 878)

Dynamic Symbols in the Part Box
Dynamic symbols can be inserted at any position in the score. They are purely graphic
symbols, and have no effect on the playback of regions they are placed in.
Note Head Symbols in the Part Box
If you drag one of these symbols onto a note, the note head changes to that of the
selected symbol. If multiple notes are selected, dragging the note head onto any one of
the notes attaches it to all notes in the selection. Altered note heads do not affect MIDI
playback.
If you want to return an altered note head to a standard display, use the same method,
with the black, round note head selected.
878 Chapter 31 Working with Notation