I have a form with lookup rules that should trigger when a value is selected from the Salesperson drop-down.  Unfortunately, it appears that the rules only trigger after you leave the Salesperson drop-down by clicking elsewhere on the form or pressing the Tab key on your keyboard. 

In this form , there are no other fields after the ones that are to be filled by the lookup rules.  It is, therefore, possible that the user will simply click the Submit button after selecting the Salesperson.  When this happens, the lookup rules appear to get triggered, but so does the message for missing required fields. 

Would it be possible to have the lookup rule trigger as soon as a value is selected from the Salesperson drop-down?

Video example of behavior: 

https://www.screencast.com/t/8FqLbd0Ss