Client scripts are not getting triggered when the action to initiate is been performed from VTB. This works fine in the native UI or Service Portal.

Steps To Reproduce:

1) Log onto OOB instance
2) Create new client script on problem table as below
Type: onChange
Table: Problem
Field name: state
Script:

function onChange(control, oldValue, newValue, isLoading, isTemplate) { 
if (isLoading || newValue == '') { 
return; 
} 
if (!isLoading) { 
if (newValue != ''){ 
g_form.setMandatory('work_notes',true); 
} 
} 

}

3) Go to problem list and "show match" a single record
4) Right-click the state column and "Show visual task board"
5) Move the task from the current state to another state
-Expected: pop up window should say "A UI Policy has prevented you from making a change" 
-Actual: the update is allowed

VTB is not designed to honour Client Scripts.

UI and/or Data Policies are the appropriate approaches to inform VTB of required fields.