Q: Smart Drums - no EDIT possible?

Dear community,

I have an IPAD PRO 12,9"

I recorded a song (piano, Smart Guitar, SMART DRUM).

for the piano and Smart guitar I can choose the Region, click twice on it an can press EDIT?

For the SMART DRUMS I can´t find the EDIT-Button.

WHAT DID I WRONG?

Greets and thanks

Axel