UI Policy and Client Script not working on "Ticket Form" [ticket] page on Service Portal

Description

A Catalog UI Policy or a Catalog Client Script to hide a catalog item variable do not work on the OOB "Ticket Form" [ticket] page on Service Portal.

Steps to Reproduce

Navigate to Maintain Items > Apple iPad 3
- /nav_to.do?uri=pc_hardware_cat_item.do?sys_id=060f3afa3731300054b6a3549dbe5d3e
Create a New Variable "SP Test"
- /nav_to.do?uri=item_option_new.do?sys_id=d89ed5b913047200efffb6004244b00b
  Type: Single Line Text
  Question: This variable is hidden by UI Policy
  Name: sp_ui_policy_test
  Default Value: This field should not be visible
Create a Service Catalog UI Policy
- /nav_to.do?uri=catalog_ui_policy.do?sys_id=035fddb913047200efffb6004244b0ea%26sysparm_view=advanced
  Applies to: A catalog Item
  Condition: none
  Applies on a Catalog Item view: true
  Applies on Catalog Tasks: true
  Applies on Requested Items: true
  On load: true
  Reverse if false: true
Create a UI Policy Action to hide variable
- /nav_to.do?uri=catalog_ui_policy_action.do?sys_id=31ff19f913047200efffb6004244b012%26sysparm_view=advanced
  Catalog Item: Apple IPad3
  Variable name: sp_ui_policy_test
  Visible: false
Navigate to SP > Order Something > Apple iPad3
- /sp?id=sc_cat_item&sys_id=060f3afa3731300054b6a3549dbe5d3e
  Notice how the variable is hidden as expected:
Submit an order
Navigate to the requested item in the Ticket form [ticket]
- /sp?id=ticket&table=sc_req_item&sys_id=3640a9f913047200efffb6004244b00c&view=sp
  Notice the variable is not hidden:

OOB ticket page (uses Ticket Fields widget):
- /nav_to.do?uri=sp_page.do?sys_id=84af292247132100ba13a5554ee4909e
OOB Widget - Ticket Fields
- /nav_to.do?uri=sp_widget.do?sys_id=5736bf52cb30020000f8d856634c9c2d

Notes:

Tested outside of SP - the UI Policy **works** directly on the sc_req_item form:
- /nav_to.do?uri=sc_req_item.do?sys_id=2975e57113447200efffb6004244b005
Tried replacing the Catalog UI Policy with a Catalog Client Script
- /nav_to.do?uri=catalog_script_client.do?sys_id=eb0769f113447200efffb6004244b062

Applies to: A catalog item

UI Type: All

Applies on a Catalog Item view: true

Applies on Requested Items: true

function onLoad() {

g_form.setDisplay('sp_ui_policy_test', false);

}

The resulting behaviour is the same as the UI Policy, it works on the order something page and outside SP, but not on the [ticket] page.

Workaround

This is expected behaviour. The widgets on the default "ticket" page (ticket-conversation and ticket-fields) do not include or contain a Form widget, so they can not use Client Scripts or UI Policies. They are simpler widgets to only show information without benefit of those conditional scripts.

As a workaround, to be able to add UI Policies or Client Scripts, use or create another page that makes use of the Form widget. Then UI Policies and Client Scripts will be available.

Related Problem: PRB741358