diff --git a/src/app/components/fieldset-container/fieldset-container.component.ts b/src/app/components/fieldset-container/fieldset-container.component.ts
index 45b87262e5329b8039177d1b4a22fe2014f720b5..d09ee6118fb4ad2208dda48e7e1d43193a9b4de7 100644
--- a/src/app/components/fieldset-container/fieldset-container.component.ts
+++ b/src/app/components/fieldset-container/fieldset-container.component.ts
@@ -74,28 +74,16 @@ export class FieldsetContainerComponent implements DoCheck, AfterViewInit {
      * Ajoute un nouveau sous-nub (Structure, PabCloisons, YAXN… selon le cas)
      * dans un nouveau fieldset
      */
-    private addSubNub(after?: FieldSet, clone: boolean = false) {
-        if (after) {
-            const newFs = this._container.addFromTemplate(0, after.indexAsKid());
-            if (this.appSetupService.enableEmptyFieldsOnFormInit && ! clone) {
-                newFs.emptyFields();
-            }
-            if (clone) {
-                // replace in-place to change properties (overkill)
-                // @WTF why only those two ?
-                newFs.setPropValue("structureType", after.properties.getPropValue("structureType"));
-                newFs.setPropValue("loiDebit", after.properties.getPropValue("loiDebit"));
-                // copy param values
-                for (const p of after.nub.prms) {
-                    newFs.nub.getParameter(p.symbol).loadObjectRepresentation(p.objectRepresentation());
-                }
-            }
-        } else {
-            const newFs = this._container.addFromTemplate(0);
-            if (this.appSetupService.enableEmptyFieldsOnFormInit && ! clone) {
-                newFs.emptyFields();
-            }
+    private addSubNub(after: FieldSet, clone: boolean = false) {
+        const prms = after.backupParameters();
+        const newFs = this._container.addFromTemplate(0, after.indexAsKid());
+        if (clone) {
+            // replace in-place to change properties (overkill)
+            // @WTF why only those two ?
+            newFs.setPropValue("structureType", after.properties.getPropValue("structureType"));
+            newFs.setPropValue("loiDebit", after.properties.getPropValue("loiDebit"));
         }
+        newFs.restoreParameters(prms);
     }
 
     private onFieldsetListChange() {
diff --git a/src/app/formulaire/elements/fieldset.ts b/src/app/formulaire/elements/fieldset.ts
index dce1e17d48ec85a85578f333ccbf908aaca69413..cf23d79c99dd52911b9d7e1e31ce7de338b45ead 100644
--- a/src/app/formulaire/elements/fieldset.ts
+++ b/src/app/formulaire/elements/fieldset.ts
@@ -15,6 +15,8 @@ import { FieldsetContainer } from "./fieldset-container";
 import { SelectFieldCustom } from "./select-field-custom";
 import { FormulaireFixedVar } from "../definition/form-fixedvar";
 import { SelectEntry } from "./select-entry";
+import { FormulaireNode } from "./formulaire-node";
+import { ServiceFactory } from "app/services/service-factory";
 
 export class FieldSet extends FormulaireElement implements Observer {
 
@@ -51,6 +53,50 @@ export class FieldSet extends FormulaireElement implements Observer {
         this.kids.push(f);
     }
 
+    /**
+     * backup NgParameters kids
+     * @returns a list of object representation with sybol, value, modification flag
+     */
+    public backupParameters(): any[] {
+        const res: any[] = [];
+        // for (const p of this.allFormElements) {
+        for (const p of this._kids) {
+            if (p instanceof NgParameter) {
+                res.push(p.objectRepresentation());
+            }
+        }
+        return res;
+    }
+
+    /**
+     * restore NgParameters kids from backup list
+     * @param backup list of NgParameter object representation
+     * @see backupParameters
+     */
+    public restoreParameters(backup: any[], except: string[] = FormulaireNode.NeverEmptyFields) {
+        // for (const p of this.allFormElements) {
+        for (const p of this._kids) {
+            if (p instanceof NgParameter) {
+                for (const bp of backup) {
+                    if (p.symbol === bp.prmDef.symbol) {
+                        // if source parameter has been user modified, copy value
+                        if (bp.modified) {
+                            p.loadObjectRepresentation(bp);
+                        }
+                        else {
+                            // can parameter be emptied ?
+                            if (ServiceFactory.applicationSetupService.enableEmptyFieldsOnFormInit && !except.includes(bp.prmDef.symbol)) {
+                                p.resetValue(this, undefined);
+                            }
+                            // else let parameter to default value
+                        }
+                        break;
+                    }
+                }
+            }
+        }
+    }
+
     public get hasInputs(): boolean {
         for (const f of this.kids) {
             if (f instanceof NgParameter) {
@@ -353,9 +399,12 @@ export class FieldSet extends FormulaireElement implements Observer {
                             });
                         }
                     } else {
-                        // for all select fields known by the form, apply received value
-                        // to associated property
                         if (this.parentForm instanceof FormulaireFixedVar) {
+                            // backup parameters
+                            const oldParams = this.backupParameters();
+
+                            // for all select fields known by the form, apply received value
+                            // to associated property
                             const selectIds = this.parentForm.selectids;
                             for (const sId of selectIds) {
                                 if (senderId === sId) {
@@ -372,6 +421,9 @@ export class FieldSet extends FormulaireElement implements Observer {
                                     }
                                 }
                             }
+
+                            // restore parameters
+                            this.restoreParameters(oldParams, FormulaireNode.NeverEmptyFields);
                         }
                     }
                     break; // switch (data.action)