Add form option to ensure all variables are evaluated before submission

If an external data source is used in a form, it's possible to submit a form before the external data source has been evaluated. This can cause other form variables that rely on the data source to have blank or inaccurate values on submission. If the external data source is experiencing heavy loads that cause a delay in Nintex receiving a response, this problem is likely to occur.

I've been told this is functioning as intended, but this seems like a shortcoming of the product. It would be nice if there was some toggle on the form that would prevent a form from being submitted before all variables (or at least external data sources) have finished evaluating.