Mutegroups and Same Note Retrigger

Hi Ken,
Now I understand.. so did a quick test:  
What you want is how I intended it originally and also worked.
# don't stop, play sample at full length (unless restarted)
Looking at the code I think functionality got lost when adding support for backtracks.
Much words for: you found a bug, so thanks for reporting.
I'll take a look if it's possible to fix.
Hans