Dynamic picklist in Stateless form

Dynamic picklist in Stateless form

Hi,

I use a stateless to add or edit existing records in a master form. In this stateless form, some fields have dynamic criteria (fieldB == input.fieldA).

My problem is when I need to fetch records from Master Form. I open StatelessForm with : 
#Form:myStateless?myID=1234

Script in StatelessForm > OnLoad :
myData = MasterForm [ID == input.myID];
input.fieldA = myData.Country;
input.fieldB = myData.Town;

As fieldB has a dynamic criteria, the value stays on "-Select-" instead of MyData.Town.

Is it possible to rectify it ? I wouldn't like to replace Dynamic Criteria by a script like  clear fieldB + fieldB:ui.add(...) but maybe I've not the choice ?

Cyril