In this article we demonstrate how to create two dependent MultiNode TreePickers (MNTPs) - the second one using the first one's selection as its root node - using some pretty XPath.
Umbraco's MultiNode TreePicker (MNTP) data type has a couple of tokens (or, more precisely, "context-aware placeholders") that can be used in the XPath query defining the starting node for the picker and represent the current or parent node - but these tokens behave differently when creating a new node than when editing an already published node. In this post we will see why and how we can make MTNP behave consistently regardless of whether the node being edited is new or existing.
Imagine this: You've got a setup where a specific node has to have a maximum of, let's say, 4 children. It can be a slider, a pricing section, a set of counters, whatever, but let's suppose it's not designed to work with more than this number of items. What do you do?