How do I fix negative stock?

The owner has a Stock correction tab in Masters → Opening Balances, with Marg’s tools in one place: allow or stop selling below zero, settle one item’s lots against each other (Marg’s Batch Updation), bring every negative item to zero, and set a category’s stock to zero (that one asks the owner PIN). Each negative item shows the bill that took it below zero, so the real mistake can be fixed. Every correction is a dated stock entry that can be cancelled.