Special Tracks
Drum Tabs
AlphaTab uses the same drum tab notation as Guitar Pro 5. Since the guitar tab staff is not meaningful on percussion track, it's hidden in case a drum tab is displayed.
Grand Staff
With Guitar Pro 6 files also grand staffs can be rendered.
Percussion since 1.1.0-alpha.45
Percussion tracks are similar to drum tabs but might have less lines than a normal staff.