Facing issue with sandbox in marking a field as mandatory conditionally

Summary:

We are trying to mark a field as mandatory or non-mandatory based on some other field input. But while doing so we are not getting the expected output. On the payables screen we are trying to make 'Type' field as mandatory based on 'Supplier Site' field input. If the value of Supplier Site is 'Neuhausen_8212', then the 'Type' field should be marked as mandatory, or else it should be displayed as non-mandatory on the screen. The EL expression used in the sandbox in 'Show Required' attribute of 'type' fields is: #{bindings.VendorSiteId.inputValue=='Neuhausen_8212'} .Please provide help in resolving this. I have attached