-start up the application, select a customer and click the Delete button or press Alt+d key;
To delete existing customer, navigate to application main
window, search for a customer, select it
in a list and eventually click Delete button or press Alt+d key combination. You will be then asked
to confirm the operation - if you do it, the customer will be permanently deleted.
NOTE
You must delete all jobs that are assigned to the customer before deleting it.