Looks very good, but if I read validation docs correctly there is no built-in validation for group of fields, like range of dates or product price range. Or eve

Looks very good, but if I read validation docs correctly there is no built-in validation for group of fields, like range of dates or product price range. Or even more complex where third field, type of product, defines lower boundary for product price range. This means you have to somehow hook up into input/validation events for each field, add validation manually and then try to put errors in the right fields even if that is not the last modified field.