Cannot tie grace note to note in different voice.
1) Create a new blank score.
2) Add a note in both voice 1 and 2 on the first beat.
3) Add a grace note to voice one, at the same pitch of the note in the second voice.
Clicking the tie button on the grace note will not tie it to the note in the second voice.
This can be worked around by making any notes which are being tied to the same voice as the grace note, and then selecting and changing their voice manually after.