This is how you make a/an cross-staff arpeggio (I guess).

How you can make a/an cross-staff arpeggio, is 1st, What type of direction you want the arpeggio to be. 2nd, When you choose it and you go and stretch the arpeggio to the other staff (whether the Bass or the Treble Clef) and when you play it, you can only hear it on the staff that you put the arpeggio on. 3rd. Right-click on the measure and staff for where it is (only on one staff). 4th. Click on the Piano Roll Editor. 5th If it is on Duration, switch it to where it says Position. 6th, For example, if you have a chord and you want to arpeggiate it, you can put it as (type it if you want), 0, 100, 200, then for the other staff/clef, do 300, 400, 500, or whatever you want it to be. 7th, You can change to the duration if you want. 8th, If you don't like it, you can always change it. I hope this really helped!