would like the dynamic dropdowns to default to a blank AND be required

I'm using the dynamic drop downs (see the Autodesk products section of the form) to default to a blank value AND then be required. I tried using the leading * but couldn't get the default value to be blank and ensure that a real value had to be selected before saving. NOTE: I'm referring to Version selection which shows after the application name is set to "Required (select version below):

I understand that you want to display the blank as the default value and to make it as required field. I see that there are only numbers in the version menu which may be causing the issue to display the blank value as the last. Please try adding any alphabet like V before the number so that you should be having the blank value as default.

Also, if you want the field to be selected as a required field you can mark the field as required from its properties.

This disables the submission of the form if  the option is left blank. Hope this information helps. Let us know if you need any further assistance. We will be happy to help.