Configures a chain of dropdowns where each subsequent dropdown's options are filtered by the value of the previous one. Useful for cascading pickers — Country → Region → City; or Brand → Model → Trim.
Conditional options
- Data Source — picks the table that contains the linked dropdown definitions. Inside that source you define each dropdown in the chain, along with the join field that ties it to its parent.
How the chain renders
The first dropdown is populated unconditionally from its source. When the user picks an option, the second dropdown's source is filtered by the join field's value (e.g. only regions belonging to the chosen country), then populated. Each subsequent dropdown works the same way.
When to use it
Anywhere the value space is naturally hierarchical and the user benefits from progressively narrowing the choice. For free-form hierarchical picks (parent-of-parent-of), consider Dropdown Box (Searchable) (DB) with a Parent ID Field instead — it renders the hierarchy as a single tree.