In Strategy Analytical Engine, apart from empty selection which empties the current element of a selector and yields a target grid no-data-return, there is another feature which allows user to revert a set selector back to unset, i.e. If it is a slicing selector, it reverts to "default dynamic selection (use first/last n)"; if it is a filter selector, it reverts to "no filter". As shown below:
A selector has two properties: status and current element. The addition of the empty selection and set-back-to-unset makes the transition between various slicing/filter selector states complete, which is summarized in the pictures below.
a) State transition of Slicing selectors:
State transition behavior in Strategy
Note: when the document initially executes, it will change the status from ‘unset’ to ‘desired’ to show first/last n elements.
b) State transition of Filter selectors:
State transition behavior,
