Fix #388 - empty fields when changing section type, too

src/app/formulaire/definition/form-section.ts

 import { FormulaireFixedVar } from "./form-fixedvar";
 import { FieldSet } from "../elements/fieldset";
+import { ServiceFactory } from "../../services/service-factory";
 
 import { IObservable, Session, SectionNub } from "jalhyd";
 
@@ -17,6 +18,11 @@ export class FormulaireSection extends FormulaireFixedVar {
                 // show / hide dependent fields
                 fs.updateFields();
             }
+            // empty fields ? only those belonging to the specific section type
+            if (ServiceFactory.instance.applicationSetupService.enableEmptyFieldsOnFormInit) {
+                // "LargeurBerge" is hackily used as LargeurFond in Rectangular and Trapez sections, omit it here
+                this.emptyFields([ "Ks", "Q", "If", "YB", "iPrec", "Y" ]);
+            }
             this.reset();
         }
     }