The FocIndex stack variable is a pointer to the current instance in a stack. In an empty stack, FocIndex is 1.
This variable is manipulated by the developer and can be used to do things such as determine which row of a stack is to be displayed on a form. A form displays data from a stack based on the value of FocIndex. For example, if a form currently displays data from the PayInfo stack and the following compute is issued:
COMPUTE PayInfo.FocIndex=15;
The fifteenth row of the stack displays in the form.