Per Document

Activate Automatic Availability Check

This function open an Availability Check

But this ignore Reservation and Work orders

Don't use it

Alternative information is

- Item History: Check all Stock- and Reservation informations
  a) Real time
  b) With more information related to last MRP run

- CTP / ATP: calculate Availability and Delivery time based on Resource planning and Material availability

Note: If you activate this setting, the Product configurator can't change the description in the sales order