Version 1.0

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.

Open

Actions :

Option Mapping : Map Options From Parent field with Options of child field.

Step 1: Select an option from parent field

Step 2: Select multiple options from child field

Step 3: Click on "Add" to save mapping which can be seen in "Option Mapping Table"

Open

Delete : Delete action in Option Mapping page allows to delete each options mapping

Edit : Edit mapped configuration.

Delete : Deleting Field mapping deletes configuration for that project along with it's respective option mapping. 

Results:

Saved cascadings can be seen on issue creation and edit issue.

Limitations : Currently it works only for single select list , we will be adding support for multi select field in future.