"Are you sure you want to delete?" key in mapping

I spent 2 hours yesterday mapping an extractor pattern and today i accidentally clicked the "delete set" button and the set vanished. I quit screen-scraper without saving and reopened the program and the mapping set was still gone.

You should put a confirmation button when deleting so people can click cancel if they accidentally click it like i did.

We actually have added that.

We actually have added that. If you update to the latest alpha, you will see it.