Prerequisite : Custom Fields of type Single Select
Configuration Settings :
To use cascading functionality, configurations can be set using below steps.
Step 1: Navigate to Add-ons → DEPENDENT SELECT LIST → Field Mappings
Step 2: Select "All Projects" if you wish to apply cascading for all project or Select project to which you wish to add cascading.
Step 3: select choice of Parent Field and Child Field then click on "Add" button.
...
Actions :
Option Mapping : Map Options From Parent field with Options of child field.
Step 1: Select an option from parent field
...
Limitations : Currently it works only for single select list , we will be adding support for multi select field in future.