1 ) I don’t think the Pickup Bar option works. Has anyone used it so far?
2 ) Is it “Pickup” (as in the UI dialog) or “Pick-up” (as in the documentation)?
For example if you want the song to be in 3/4 time signature, but the first bar should only be one quarter note in length:
Edit the time signature in first bar to 1/4
Add a 3/4 time signature in the second bar
Add e.g. a quarter note in the first bar, and a half note and a quarter note in the second bar
Activate pickup bar for the 1/4 time signature
Result: The 1/4 time signature in the first bar is replaced by the actual 3/4 time signature the song is in, but the length of the first bar is only a quarter note. The 3/4 time signature in the second bar is removed.