I unintentionally selected, copied, and pasted an entire 8-hour clip–instead of the 5 seconds of silence intended. I was surprised to find there’s no way to cancel, escape from, or stop the paste, which took quite a long time. Is there a reason that feature doesn’t exist?
My workaround would be to
- crash Audacity (for example on Windows with Task Manager)
- relaubnch Auudaity
- rely on Recovery to restore the project.
Peter.
Thanks! Also might make sense to allow “cancel” 
To make such an “enhancement request” you would need to post it on Muse’s GitHub issues log:
You need a GitHub account for that, but those are free.
Peter.