Client Script onChange does not work first time around

[Lee Jones]

I'm relatively new to ServiceNow Client Scripts. I'm trying to write a script that makes the 'comments' field mandatory specifically when incident 'state' changes to newValue In Progress (2), from oldValue New (1).

The script seems to work successfully, apart from when I initially change the state field. All subsequent state changes work as expected, just not the first.

Example: I open an incident which is in state New. I select 'In Progress' from the dropdown - State is not mandatory. I then select another state from the drop-down before reselecting 'In Progress' - only then does State become mandatory.

I have tested this in both a PDI (Utah) and my organisations dev environment (Utah). Both have the same outcome. I would appreciate some help with this. Many thanks.

Script:

function onChange(control, oldValue, newValue, isLoading, isTemplate) {

   if (isLoading || newValue === '') {

      return;

   }

   //Type appropriate comment here, and begin script below

   if(newValue == '2' && oldValue == '1'){  

        g_form.setMandatory('comments',true);       

        g_form.setReadOnly('work_notes',true);

        g_form.showFieldMsg('comments','Please enter a customer update, preferably using a suitable template','info');

    }

    else {

        g_form.setMandatory('comments',false);

        g_form.setReadOnly('work_notes',false);

        g_form.hideFieldMsg('comments','Please enter a customer update, preferably using a suitable template','error');

    }

}

[Anurag Tripathi]

That is weird.

I wonder if there is another script running at a latter order or a ui policy that overrides the comments field behavior