How to make supplier field as mandatory when the new supplier is enabled

Summary:

While creating the Non Catalog request, If I select New Supplier checkbox, through personalization how to make the Supplier field as Mandatory.

Could you please let me know the condition to be written, I tried this and it's not working

If (New Supplier == 'Yes')

{

return true;

}

else

{

return false;

}

Content (required):

Version (include the version you are using, if applicable):

21C

Code Snippet (add any code snippets that support your topic, if applicable):