The curly braces turn the aggregation into a Fixed LOD, running the aggregation across all rows in context. The IF statement returns the parameter value when there is a relevant matching Order Date. When there’s no match, it instead returns the maximum Order Date value in context. Whichever...
Currently if you sent the date filter to the max value (say Sept 2014) and publish it, it will always show that in the filter. If I come back and look at it in December, it will still stay Sept 2014. It would be nice to have the option for that to now display whatever the late...