export slice with 100% transprancy?

Hello,
I try to export slices with transparent background, but don’t have good result


I try also in svg but smae result the number of tablature are also not transparent!
Some experience?
Best regards
Dup

Hello,
Finally I search and found the solution!
To the team of Dorico: you are crazy: you think about a lot of things!! Thanks
transparancy_number.png