[FinalBuilder Professional Edition]
The Stack/Queue Is Empty action is used to test if the list contains any items or not.
Stack/Queue name - select the name of the list which you want to test. If there aren't any items in this list, you need to use the Stack/Queue Define action to create a new list.
Put is empty boolean into Variable - specify a variable to set to a boolean indicating if the list is empty or not (True means list is empty).
Fail action if... - if you want the action to fail if the list is empty or if the list isn't empty, then set this property.