diff --git a/src/app/examples/pab-complete-chain.json b/src/app/examples/pab-complete-chain.json
index ee99ec0c84eb4ae574ea2e265a18a22517ca8d9c..ca9e460f1ab42027a2d272a7918a39731084a71b 100644
--- a/src/app/examples/pab-complete-chain.json
+++ b/src/app/examples/pab-complete-chain.json
@@ -1 +1,570 @@
-{"header":{"source":"jalhyd","format_version":"1.1","created":"2019-09-06T08:40:17.092Z"},"session":[{"uid":"NjdmM3","props":{"calcType":"PabChute","nodeType":"None"},"meta":{"title":"PAB : chute"},"children":[],"parameters":[{"symbol":"Z1","mode":"SINGLE","value":29.99},{"symbol":"Z2","mode":"SINGLE","value":26.81},{"symbol":"DH","mode":"CALCUL"}]},{"uid":"eWNjdG","props":{"calcType":"PabNombre","nodeType":"None"},"meta":{"title":"PAB : nombre"},"children":[],"parameters":[{"symbol":"DHT","mode":"LINK","targetNub":"NjdmM3","targetParam":"DH"},{"symbol":"N","mode":"SINGLE","value":14},{"symbol":"DH","mode":"CALCUL"}]},{"uid":"dXM4em","props":{"calcType":"PabPuissance","nodeType":"None"},"meta":{"title":"PAB : puissance"},"children":[],"parameters":[{"symbol":"DH","mode":"LINK","targetNub":"eWNjdG","targetParam":"DH"},{"symbol":"Q","mode":"SINGLE","value":1.8},{"symbol":"V","mode":"CALCUL"},{"symbol":"PV","mode":"SINGLE","value":140}]},{"uid":"bzNlaX","props":{"calcType":"PabDimensions","nodeType":"None"},"meta":{"title":"PAB : dimensions"},"children":[],"parameters":[{"symbol":"L","mode":"SINGLE","value":5},{"symbol":"W","mode":"SINGLE","value":3.6},{"symbol":"Y","mode":"CALCUL"},{"symbol":"V","mode":"LINK","targetNub":"dXM4em","targetParam":"V"}]},{"uid":"cGI5d3","props":{"calcType":"Cloisons","nodeType":"None"},"meta":{"title":"Cloisons"},"children":[{"uid":"ZzZzbD","props":{"calcType":"Structure","structureType":"SeuilRectangulaire","loiDebit":"WeirSubmergedLarinier","nodeType":"None"},"children":[],"parameters":[{"symbol":"h1","mode":"CALCUL"},{"symbol":"L","mode":"SINGLE","value":0.5},{"symbol":"CdWSL","mode":"SINGLE","value":0.83}]}],"parameters":[{"symbol":"Q","mode":"LINK","targetNub":"dXM4em","targetParam":"Q"},{"symbol":"Z1","mode":"SINGLE","value":30.14},{"symbol":"LB","mode":"SINGLE","value":4.5},{"symbol":"BB","mode":"LINK","targetNub":"bzNlaX","targetParam":"W"},{"symbol":"PB","mode":"SINGLE","value":2.5},{"symbol":"DH","mode":"LINK","targetNub":"eWNjdG","targetParam":"DH"}]},{"uid":"Y3k4bj","props":{"calcType":"Pab"},"meta":{"title":"PAB"},"children":[{"uid":"ampiN3","props":{"calcType":"Cloisons","nodeType":"None"},"children":[{"uid":"Yzgxa2","props":{"calcType":"Structure","structureType":"SeuilRectangulaire","loiDebit":"WeirSubmergedLarinier","nodeType":"None"},"children":[],"parameters":[{"symbol":"ZDV","mode":"SINGLE","value":28.085},{"symbol":"L","mode":"SINGLE","value":0.5},{"symbol":"CdWSL","mode":"SINGLE","value":0.83}]}],"parameters":[{"symbol":"LB","mode":"SINGLE","value":4.5},{"symbol":"BB","mode":"SINGLE","value":3.6},{"symbol":"ZRMB","mode":"SINGLE","value":27.413},{"symbol":"ZRAM","mode":"SINGLE","value":27.526},{"symbol":"QA","mode":"SINGLE","value":0}]},{"uid":"c3RmMz","props":{"calcType":"Cloisons","nodeType":"None"},"children":[{"uid":"dmwyem","props":{"calcType":"Structure","structureType":"SeuilRectangulaire","loiDebit":"WeirSubmergedLarinier","nodeType":"None"},"children":[],"parameters":[{"symbol":"ZDV","mode":"SINGLE","value":27.858},{"symbol":"L","mode":"SINGLE","value":0.5},{"symbol":"CdWSL","mode":"SINGLE","value":0.83}]}],"parameters":[{"symbol":"LB","mode":"SINGLE","value":4.5},{"symbol":"BB","mode":"SINGLE","value":3.6},{"symbol":"ZRMB","mode":"SINGLE","value":27.186},{"symbol":"ZRAM","mode":"SINGLE","value":27.299},{"symbol":"QA","mode":"SINGLE","value":0}]},{"uid":"cTlydj","props":{"calcType":"Cloisons","nodeType":"None"},"children":[{"uid":"cWQ5aX","props":{"calcType":"Structure","structureType":"SeuilRectangulaire","loiDebit":"WeirSubmergedLarinier","nodeType":"None"},"children":[],"parameters":[{"symbol":"ZDV","mode":"SINGLE","value":27.631},{"symbol":"L","mode":"SINGLE","value":0.5},{"symbol":"CdWSL","mode":"SINGLE","value":0.83}]}],"parameters":[{"symbol":"LB","mode":"SINGLE","value":4.5},{"symbol":"BB","mode":"SINGLE","value":3.6},{"symbol":"ZRMB","mode":"SINGLE","value":26.959},{"symbol":"ZRAM","mode":"SINGLE","value":27.072},{"symbol":"QA","mode":"SINGLE","value":0}]},{"uid":"emRkMX","props":{"calcType":"Cloisons","nodeType":"None"},"children":[{"uid":"aG1xbj","props":{"calcType":"Structure","structureType":"SeuilRectangulaire","loiDebit":"WeirSubmergedLarinier","nodeType":"None"},"children":[],"parameters":[{"symbol":"ZDV","mode":"SINGLE","value":27.404},{"symbol":"L","mode":"SINGLE","value":0.5},{"symbol":"CdWSL","mode":"SINGLE","value":0.83}]}],"parameters":[{"symbol":"LB","mode":"SINGLE","value":4.5},{"symbol":"BB","mode":"SINGLE","value":3.6},{"symbol":"ZRMB","mode":"SINGLE","value":26.731},{"symbol":"ZRAM","mode":"SINGLE","value":26.845},{"symbol":"QA","mode":"SINGLE","value":0}]},{"uid":"eG9hdT","props":{"calcType":"Cloisons","nodeType":"None"},"children":[{"uid":"M3Z5ZX","props":{"calcType":"Structure","structureType":"SeuilRectangulaire","loiDebit":"WeirSubmergedLarinier","nodeType":"None"},"children":[],"parameters":[{"symbol":"ZDV","mode":"SINGLE","value":27.177},{"symbol":"L","mode":"SINGLE","value":0.5},{"symbol":"CdWSL","mode":"SINGLE","value":0.83}]}],"parameters":[{"symbol":"LB","mode":"SINGLE","value":4.5},{"symbol":"BB","mode":"SINGLE","value":3.6},{"symbol":"ZRMB","mode":"SINGLE","value":26.504},{"symbol":"ZRAM","mode":"SINGLE","value":26.618},{"symbol":"QA","mode":"SINGLE","value":0}]}],"parameters":[{"symbol":"Q","mode":"SINGLE","value":1.8},{"symbol":"Z1","mode":"CALCUL"},{"symbol":"Z2","mode":"SINGLE","value":28.778}],"downWall":{"uid":"bWExN2","props":{"calcType":"CloisonAval"},"children":[{"uid":"bm0zcD","props":{"calcType":"Structure","structureType":"SeuilRectangulaire","loiDebit":"WeirSubmergedLarinier","nodeType":"None"},"children":[],"parameters":[{"symbol":"ZDV","mode":"SINGLE","value":26.95},{"symbol":"L","mode":"SINGLE","value":0.5},{"symbol":"CdWSL","mode":"SINGLE","value":0.83}]}],"parameters":[{"symbol":"ZRAM","mode":"SINGLE","value":26.391}]}}]}
\ No newline at end of file
+{
+    "header": {
+        "source": "jalhyd",
+        "format_version": "1.1",
+        "created": "2019-09-06T08:40:17.092Z"
+    },
+    "session": [
+        {
+            "uid": "NjdmM3",
+            "props": {
+                "calcType": "PabChute"
+            },
+            "meta": {
+                "title": "PAB : chute"
+            },
+            "children": [],
+            "parameters": [
+                {
+                    "symbol": "Z1",
+                    "mode": "SINGLE",
+                    "value": 29.99
+                },
+                {
+                    "symbol": "Z2",
+                    "mode": "SINGLE",
+                    "value": 26.81
+                },
+                {
+                    "symbol": "DH",
+                    "mode": "CALCUL"
+                }
+            ]
+        },
+        {
+            "uid": "eWNjdG",
+            "props": {
+                "calcType": "PabNombre"
+            },
+            "meta": {
+                "title": "PAB : nombre"
+            },
+            "children": [],
+            "parameters": [
+                {
+                    "symbol": "DHT",
+                    "mode": "LINK",
+                    "targetNub": "NjdmM3",
+                    "targetParam": "DH"
+                },
+                {
+                    "symbol": "N",
+                    "mode": "SINGLE",
+                    "value": 14
+                },
+                {
+                    "symbol": "DH",
+                    "mode": "CALCUL"
+                }
+            ]
+        },
+        {
+            "uid": "dXM4em",
+            "props": {
+                "calcType": "PabPuissance"
+            },
+            "meta": {
+                "title": "PAB : puissance"
+            },
+            "children": [],
+            "parameters": [
+                {
+                    "symbol": "DH",
+                    "mode": "LINK",
+                    "targetNub": "eWNjdG",
+                    "targetParam": "DH"
+                },
+                {
+                    "symbol": "Q",
+                    "mode": "SINGLE",
+                    "value": 1.8
+                },
+                {
+                    "symbol": "V",
+                    "mode": "CALCUL"
+                },
+                {
+                    "symbol": "PV",
+                    "mode": "SINGLE",
+                    "value": 140
+                }
+            ]
+        },
+        {
+            "uid": "bzNlaX",
+            "props": {
+                "calcType": "PabDimensions"
+            },
+            "meta": {
+                "title": "PAB : dimensions"
+            },
+            "children": [],
+            "parameters": [
+                {
+                    "symbol": "L",
+                    "mode": "SINGLE",
+                    "value": 5
+                },
+                {
+                    "symbol": "W",
+                    "mode": "SINGLE",
+                    "value": 3.6
+                },
+                {
+                    "symbol": "Y",
+                    "mode": "CALCUL"
+                },
+                {
+                    "symbol": "V",
+                    "mode": "LINK",
+                    "targetNub": "dXM4em",
+                    "targetParam": "V"
+                }
+            ]
+        },
+        {
+            "uid": "cGI5d3",
+            "props": {
+                "calcType": "Cloisons"
+            },
+            "meta": {
+                "title": "Cloisons"
+            },
+            "children": [
+                {
+                    "uid": "ZzZzbD",
+                    "props": {
+                        "calcType": "Structure",
+                        "structureType": "SeuilRectangulaire",
+                        "loiDebit": "WeirSubmergedLarinier"
+                    },
+                    "children": [],
+                    "parameters": [
+                        {
+                            "symbol": "h1",
+                            "mode": "CALCUL"
+                        },
+                        {
+                            "symbol": "L",
+                            "mode": "SINGLE",
+                            "value": 0.5
+                        },
+                        {
+                            "symbol": "CdWSL",
+                            "mode": "SINGLE",
+                            "value": 0.83
+                        }
+                    ]
+                }
+            ],
+            "parameters": [
+                {
+                    "symbol": "Q",
+                    "mode": "LINK",
+                    "targetNub": "dXM4em",
+                    "targetParam": "Q"
+                },
+                {
+                    "symbol": "Z1",
+                    "mode": "SINGLE",
+                    "value": 30.14
+                },
+                {
+                    "symbol": "LB",
+                    "mode": "SINGLE",
+                    "value": 4.5
+                },
+                {
+                    "symbol": "BB",
+                    "mode": "LINK",
+                    "targetNub": "bzNlaX",
+                    "targetParam": "W"
+                },
+                {
+                    "symbol": "PB",
+                    "mode": "SINGLE",
+                    "value": 2.5
+                },
+                {
+                    "symbol": "DH",
+                    "mode": "LINK",
+                    "targetNub": "eWNjdG",
+                    "targetParam": "DH"
+                }
+            ]
+        },
+        {
+            "uid": "Y3k4bj",
+            "props": {
+                "calcType": "Pab"
+            },
+            "meta": {
+                "title": "PAB"
+            },
+            "children": [
+                {
+                    "uid": "ampiN3",
+                    "props": {
+                        "calcType": "Cloisons"
+                    },
+                    "children": [
+                        {
+                            "uid": "Yzgxa2",
+                            "props": {
+                                "calcType": "Structure",
+                                "structureType": "SeuilRectangulaire",
+                                "loiDebit": "WeirSubmergedLarinier"
+                            },
+                            "children": [],
+                            "parameters": [
+                                {
+                                    "symbol": "ZDV",
+                                    "mode": "SINGLE",
+                                    "value": 28.085
+                                },
+                                {
+                                    "symbol": "L",
+                                    "mode": "SINGLE",
+                                    "value": 0.5
+                                },
+                                {
+                                    "symbol": "CdWSL",
+                                    "mode": "SINGLE",
+                                    "value": 0.83
+                                }
+                            ]
+                        }
+                    ],
+                    "parameters": [
+                        {
+                            "symbol": "LB",
+                            "mode": "SINGLE",
+                            "value": 4.5
+                        },
+                        {
+                            "symbol": "BB",
+                            "mode": "SINGLE",
+                            "value": 3.6
+                        },
+                        {
+                            "symbol": "ZRMB",
+                            "mode": "SINGLE",
+                            "value": 27.413
+                        },
+                        {
+                            "symbol": "ZRAM",
+                            "mode": "SINGLE",
+                            "value": 27.526
+                        },
+                        {
+                            "symbol": "QA",
+                            "mode": "SINGLE",
+                            "value": 0
+                        }
+                    ]
+                },
+                {
+                    "uid": "c3RmMz",
+                    "props": {
+                        "calcType": "Cloisons"
+                    },
+                    "children": [
+                        {
+                            "uid": "dmwyem",
+                            "props": {
+                                "calcType": "Structure",
+                                "structureType": "SeuilRectangulaire",
+                                "loiDebit": "WeirSubmergedLarinier"
+                            },
+                            "children": [],
+                            "parameters": [
+                                {
+                                    "symbol": "ZDV",
+                                    "mode": "SINGLE",
+                                    "value": 27.858
+                                },
+                                {
+                                    "symbol": "L",
+                                    "mode": "SINGLE",
+                                    "value": 0.5
+                                },
+                                {
+                                    "symbol": "CdWSL",
+                                    "mode": "SINGLE",
+                                    "value": 0.83
+                                }
+                            ]
+                        }
+                    ],
+                    "parameters": [
+                        {
+                            "symbol": "LB",
+                            "mode": "SINGLE",
+                            "value": 4.5
+                        },
+                        {
+                            "symbol": "BB",
+                            "mode": "SINGLE",
+                            "value": 3.6
+                        },
+                        {
+                            "symbol": "ZRMB",
+                            "mode": "SINGLE",
+                            "value": 27.186
+                        },
+                        {
+                            "symbol": "ZRAM",
+                            "mode": "SINGLE",
+                            "value": 27.299
+                        },
+                        {
+                            "symbol": "QA",
+                            "mode": "SINGLE",
+                            "value": 0
+                        }
+                    ]
+                },
+                {
+                    "uid": "cTlydj",
+                    "props": {
+                        "calcType": "Cloisons"
+                    },
+                    "children": [
+                        {
+                            "uid": "cWQ5aX",
+                            "props": {
+                                "calcType": "Structure",
+                                "structureType": "SeuilRectangulaire",
+                                "loiDebit": "WeirSubmergedLarinier"
+                            },
+                            "children": [],
+                            "parameters": [
+                                {
+                                    "symbol": "ZDV",
+                                    "mode": "SINGLE",
+                                    "value": 27.631
+                                },
+                                {
+                                    "symbol": "L",
+                                    "mode": "SINGLE",
+                                    "value": 0.5
+                                },
+                                {
+                                    "symbol": "CdWSL",
+                                    "mode": "SINGLE",
+                                    "value": 0.83
+                                }
+                            ]
+                        }
+                    ],
+                    "parameters": [
+                        {
+                            "symbol": "LB",
+                            "mode": "SINGLE",
+                            "value": 4.5
+                        },
+                        {
+                            "symbol": "BB",
+                            "mode": "SINGLE",
+                            "value": 3.6
+                        },
+                        {
+                            "symbol": "ZRMB",
+                            "mode": "SINGLE",
+                            "value": 26.959
+                        },
+                        {
+                            "symbol": "ZRAM",
+                            "mode": "SINGLE",
+                            "value": 27.072
+                        },
+                        {
+                            "symbol": "QA",
+                            "mode": "SINGLE",
+                            "value": 0
+                        }
+                    ]
+                },
+                {
+                    "uid": "emRkMX",
+                    "props": {
+                        "calcType": "Cloisons"
+                    },
+                    "children": [
+                        {
+                            "uid": "aG1xbj",
+                            "props": {
+                                "calcType": "Structure",
+                                "structureType": "SeuilRectangulaire",
+                                "loiDebit": "WeirSubmergedLarinier"
+                            },
+                            "children": [],
+                            "parameters": [
+                                {
+                                    "symbol": "ZDV",
+                                    "mode": "SINGLE",
+                                    "value": 27.404
+                                },
+                                {
+                                    "symbol": "L",
+                                    "mode": "SINGLE",
+                                    "value": 0.5
+                                },
+                                {
+                                    "symbol": "CdWSL",
+                                    "mode": "SINGLE",
+                                    "value": 0.83
+                                }
+                            ]
+                        }
+                    ],
+                    "parameters": [
+                        {
+                            "symbol": "LB",
+                            "mode": "SINGLE",
+                            "value": 4.5
+                        },
+                        {
+                            "symbol": "BB",
+                            "mode": "SINGLE",
+                            "value": 3.6
+                        },
+                        {
+                            "symbol": "ZRMB",
+                            "mode": "SINGLE",
+                            "value": 26.731
+                        },
+                        {
+                            "symbol": "ZRAM",
+                            "mode": "SINGLE",
+                            "value": 26.845
+                        },
+                        {
+                            "symbol": "QA",
+                            "mode": "SINGLE",
+                            "value": 0
+                        }
+                    ]
+                },
+                {
+                    "uid": "eG9hdT",
+                    "props": {
+                        "calcType": "Cloisons"
+                    },
+                    "children": [
+                        {
+                            "uid": "M3Z5ZX",
+                            "props": {
+                                "calcType": "Structure",
+                                "structureType": "SeuilRectangulaire",
+                                "loiDebit": "WeirSubmergedLarinier"
+                            },
+                            "children": [],
+                            "parameters": [
+                                {
+                                    "symbol": "ZDV",
+                                    "mode": "SINGLE",
+                                    "value": 27.177
+                                },
+                                {
+                                    "symbol": "L",
+                                    "mode": "SINGLE",
+                                    "value": 0.5
+                                },
+                                {
+                                    "symbol": "CdWSL",
+                                    "mode": "SINGLE",
+                                    "value": 0.83
+                                }
+                            ]
+                        }
+                    ],
+                    "parameters": [
+                        {
+                            "symbol": "LB",
+                            "mode": "SINGLE",
+                            "value": 4.5
+                        },
+                        {
+                            "symbol": "BB",
+                            "mode": "SINGLE",
+                            "value": 3.6
+                        },
+                        {
+                            "symbol": "ZRMB",
+                            "mode": "SINGLE",
+                            "value": 26.504
+                        },
+                        {
+                            "symbol": "ZRAM",
+                            "mode": "SINGLE",
+                            "value": 26.618
+                        },
+                        {
+                            "symbol": "QA",
+                            "mode": "SINGLE",
+                            "value": 0
+                        }
+                    ]
+                }
+            ],
+            "parameters": [
+                {
+                    "symbol": "Q",
+                    "mode": "SINGLE",
+                    "value": 1.8
+                },
+                {
+                    "symbol": "Z1",
+                    "mode": "CALCUL"
+                },
+                {
+                    "symbol": "Z2",
+                    "mode": "SINGLE",
+                    "value": 28.778
+                }
+            ],
+            "downWall": {
+                "uid": "bWExN2",
+                "props": {
+                    "calcType": "CloisonAval"
+                },
+                "children": [
+                    {
+                        "uid": "bm0zcD",
+                        "props": {
+                            "calcType": "Structure",
+                            "structureType": "SeuilRectangulaire",
+                            "loiDebit": "WeirSubmergedLarinier"
+                        },
+                        "children": [],
+                        "parameters": [
+                            {
+                                "symbol": "ZDV",
+                                "mode": "SINGLE",
+                                "value": 26.95
+                            },
+                            {
+                                "symbol": "L",
+                                "mode": "SINGLE",
+                                "value": 0.5
+                            },
+                            {
+                                "symbol": "CdWSL",
+                                "mode": "SINGLE",
+                                "value": 0.83
+                            }
+                        ]
+                    }
+                ],
+                "parameters": [
+                    {
+                        "symbol": "ZRAM",
+                        "mode": "SINGLE",
+                        "value": 26.391
+                    }
+                ]
+            }
+        }
+    ]
+}
\ No newline at end of file
diff --git a/src/app/formulaire/definition/concrete/form-courbe-remous.ts b/src/app/formulaire/definition/concrete/form-courbe-remous.ts
index 0cd6c20802c1c348554862773592552bfb1886dd..ce98814c1544a6d32ba0184bbcdf96fec384cbbb 100644
--- a/src/app/formulaire/definition/concrete/form-courbe-remous.ts
+++ b/src/app/formulaire/definition/concrete/form-courbe-remous.ts
@@ -59,7 +59,7 @@ export class FormulaireCourbeRemous extends FormulaireBase {
             switch (sender.id) {
                 case "fs_section":
                     // replace underlying section without replacing whole Nub
-                    const newSect = Session.getInstance().createSection(sender.properties.getPropValue("nodeType"));
+                    const newSect = Session.getInstance().createSection(data.value);
                     (this._currentNub as SectionNub).setSection(newSect);
                     // reflect changes in GUI
                     for (const fs of this.allFieldsets) {
diff --git a/src/app/formulaire/definition/concrete/form-regime-uniforme.ts b/src/app/formulaire/definition/concrete/form-regime-uniforme.ts
index bb4cbd0a9ef74c761e29c49cec44b917b88b19de..4e8b483148e512ece8d96651426a3e0466b580c9 100644
--- a/src/app/formulaire/definition/concrete/form-regime-uniforme.ts
+++ b/src/app/formulaire/definition/concrete/form-regime-uniforme.ts
@@ -30,12 +30,14 @@ export class FormulaireRegimeUniforme extends FormulaireBase implements Observer
 
     update(sender: IObservable, data: any) {
 
+        console.log(">> Update Form RU", sender.constructor.name, data);
+
         super.update(sender, data);
 
         // changement de propriété du FieldSet contenant le select de choix du type de section
         if (sender instanceof FieldSet && sender.id === "fs_section" && data.action === "propertyChange") {
             // replace underlying section without replacing whole Nub
-            const newSect = Session.getInstance().createSection(sender.properties.getPropValue("nodeType"));
+            const newSect = Session.getInstance().createSection(data.value);
             (this._currentNub as SectionNub).setSection(newSect);
             // reflect changes in GUI
             for (const fs of this.allFieldsets) {
diff --git a/src/app/formulaire/definition/concrete/form-section-parametree.ts b/src/app/formulaire/definition/concrete/form-section-parametree.ts
index 0e623cd402c44e46275cbcd5a711e0803b11e412..3bb8a56c757d4bac5384070e9605527aff47f60c 100644
--- a/src/app/formulaire/definition/concrete/form-section-parametree.ts
+++ b/src/app/formulaire/definition/concrete/form-section-parametree.ts
@@ -34,8 +34,8 @@ export class FormulaireSectionParametree extends FormulaireBase {
     // interface Observer
 
     update(sender: IObservable, data: any) {
-
         // super.update(sender, data);
+
         if (sender instanceof Nub) {
             switch (data.action) {
                 case "resultUpdated":
@@ -50,7 +50,7 @@ export class FormulaireSectionParametree extends FormulaireBase {
             switch (sender.id) {
                 case "fs_section":
                     // replace underlying section without replacing whole Nub
-                    const newSect = Session.getInstance().createSection(sender.properties.getPropValue("nodeType"));
+                    const newSect = Session.getInstance().createSection(data.value);
                     (this._currentNub as SectionNub).setSection(newSect);
                     // reflect changes in GUI
                     for (const fs of this.allFieldsets) {
diff --git a/src/app/formulaire/definition/form-definition.ts b/src/app/formulaire/definition/form-definition.ts
index 2ba17671bcb97125f20319a2bf72cb94938924af..41094efef5da07b84fb98073a34d9b35891a653b 100644
--- a/src/app/formulaire/definition/form-definition.ts
+++ b/src/app/formulaire/definition/form-definition.ts
@@ -29,6 +29,9 @@ export abstract class FormulaireDefinition extends FormulaireNode implements Obs
     /** propriétés par défaut (lues si _currentNub === undefined ) */
     protected _props = {};
 
+    /** for SectionNubs only */
+    protected _defaultNodeType;
+
     /** aide en ligne pour les résultats */
     protected _resultsHelpLinks: { [key: string]: string };
 
@@ -100,12 +103,13 @@ export abstract class FormulaireDefinition extends FormulaireNode implements Obs
      */
     public initNub(props?: Props) {
         const p = props ? props : new Props(this.defaultProperties);
-        const p2 = p.clone();
         this.currentNub = Session.getInstance().createSessionNub(p);
+
         if (this.currentNub instanceof SectionNub) {
             // add new Section as first child, from given nodeType
-            p2.setPropValue("calcType", CalculatorType.Section);
-            const section = Session.getInstance().createNub(p2);
+            p.setPropValue("calcType", CalculatorType.Section);
+            p.setPropValue("nodeType", this._defaultNodeType);
+            const section = Session.getInstance().createNub(p);
             this.currentNub.setSection(section as acSection);
         }
     }
@@ -138,7 +142,7 @@ export abstract class FormulaireDefinition extends FormulaireNode implements Obs
     protected parseOptions(json: {}) {
         const dnt = json["defaultNodeType"];
         if (dnt !== undefined) {
-            this._props["nodeType"] = ComputeNodeType[dnt];
+            this._defaultNodeType = ComputeNodeType[dnt];
         }
         this._helpLink = json["help"];
         this._resultsHelpLinks = json["resultsHelp"];
diff --git a/src/app/formulaire/fieldset.ts b/src/app/formulaire/fieldset.ts
index 6bdc4f1c4ca7bfba337d15eee124903aa82dcf70..494e64140121f81b1ac62b9bf0e6f90aefa3e021 100644
--- a/src/app/formulaire/fieldset.ts
+++ b/src/app/formulaire/fieldset.ts
@@ -309,11 +309,6 @@ export class FieldSet extends FormulaireElement implements Observer {
         const calc_type: CalculatorType = currentCt ? currentCt : (ct ? CalculatorType[ct] : parentForm.calculatorType);
         this.setPropValue("calcType", calc_type);
 
-        const dnt: string = json["defaultNodeType"];
-        const currentNt = this.properties.getPropValue("nodeType");
-        const node_type: ComputeNodeType = currentNt ? currentNt : (dnt ? ComputeNodeType[dnt] : parentForm.nodeType);
-        this.setPropValue("nodeType", node_type);
-
         this.setPropertyValueFromConfig(json, "defaultStructType", "structureType");
         this.setPropertyValueFromConfig(json, "defaultLoiDebit", "loiDebit", LoiDebit);
         this.setPropertyValueFromConfig(json, "methodeResolution", "methodeResolution", MethodeResolution);
@@ -373,8 +368,17 @@ export class FieldSet extends FormulaireElement implements Observer {
                 case "select":
                     const senderId: string = sender.id.replace(/\d+$/, "");
                     switch (senderId) {
-                        case "select_section": // sections paramétrées
-                            this.setPropValue("nodeType", data.value.value);
+                        case "select_section": // sections paramétrées, courbes de remous, régimes uniformes
+                            // "nodeType" is a property of the section child, not of the parent
+                            const oldNodeType = this.nub.getChildren()[0].properties.getPropValue("nodeType");
+                            if (oldNodeType !== data.value.value) { // avoid infinite loops
+                                // manually notify parent so that it replaces the child Nub @WARNING clodo trick
+                                this.parentForm.update(this, {
+                                    action: "propertyChange",
+                                    name: "nodeType",
+                                    value: data.value.value
+                                });
+                            }
                             break;
                         case "select_structure": // ouvrages parallèles
                             this.setPropValue("structureType", data.value.value);
diff --git a/src/app/formulaire/formulaire-element.ts b/src/app/formulaire/formulaire-element.ts
index c09ea72af70cb47322f62759208c9af0b076bda7..05c5965471ebdfbebdf85326dc219ffac5f2101b 100644
--- a/src/app/formulaire/formulaire-element.ts
+++ b/src/app/formulaire/formulaire-element.ts
@@ -3,6 +3,7 @@ import { StringMap } from "../stringmap";
 import { DeepFormulaireElementIterator } from "./form-iterator/deep-element-iterator";
 import { I18nService } from "../services/internationalisation.service";
 import { ServiceFactory } from "../services/service-factory";
+import { FormulaireDefinition } from "./definition/form-definition";
 
 /**
  * élément (enfant) du formulaire : fieldset, input, container, ...
@@ -55,7 +56,7 @@ export abstract class FormulaireElement extends FormulaireNode {
     /**
      * formulaire parent
      */
-    public get parentForm(): FormulaireNode {
+    public get parentForm(): FormulaireDefinition {
         let res = this.parent;
         // while (!(res instanceof FormulaireDefinition))
         while (!("calculatorName" in res)) {
@@ -63,7 +64,7 @@ export abstract class FormulaireElement extends FormulaireNode {
             // casser les dépendances circulaires d'import
             res = res.parent;
         }
-        return res;
+        return (res as FormulaireDefinition);
     }
 
     /**