Choose Document > Document Options > Notes and Rests. The Notes and Rests options appear.
Choose Notehead Characters > Quarter/Eighth, and then click
Select. The Symbol Selection dialog box appears, displaying every
character in the music font.
Double-click any blank square. Repeat
with the Half, Whole, and Double Whole notehead types, if they appear
in your piece.
Click OK. To restore the noteheads,
repeat the process. Instead of double-clicking a blank square, however,
double-click the appropriate notehead shape in the palette.