fix: variable results graph: select entries not translated when modifying langage setting

refs #586

src/app/components/fixedvar-results/var-results.component.ts

-import { Component, ViewChild, ElementRef, Input } from "@angular/core";
+import { Component, ViewChild, ElementRef, Input, OnInit } from "@angular/core";
 
 import { MatDialog } from "@angular/material/dialog";
 
@@ -17,7 +17,7 @@ import { longestVarParam } from "../../../app/util";
         "./var-results.component.scss"
     ]
 })
-export class VarResultsComponent extends ResultsComponentDirective implements Observer {
+export class VarResultsComponent extends ResultsComponentDirective implements Observer, OnInit {
 
     /** size of the longest variated parameter */
     public size: number;
@@ -196,6 +196,10 @@ export class VarResultsComponent extends ResultsComponentDirective implements Ob
         );
     }
 
+    ngOnInit(): void {
+        this._varResults.updateCalculatedParameterHeader();
+    }
+
     // Observer interface
 
     update(sender: any, data: any): void {

src/app/results/param-calc-results.ts

@@ -12,7 +12,7 @@ export abstract class CalculatedParamResults extends CalculatorResults {
     protected _calculatedParam: NgParameter;
 
     /** titre de la colonne du paramètre calculé */
-    public calculatedParameterHeader: string;
+    private _calculatedParameterHeader: string;
 
     /** résultat du calcul sur le paramètre calculé */
     public result: Result;
@@ -22,7 +22,7 @@ export abstract class CalculatedParamResults extends CalculatorResults {
 
     public reset() {
         this._calculatedParam = undefined;
-        this.calculatedParameterHeader = undefined;
+        this._calculatedParameterHeader = undefined;
         this.result = undefined;
     }
 
@@ -32,7 +32,17 @@ export abstract class CalculatedParamResults extends CalculatorResults {
 
     public set calculatedParameter(p: NgParameter) {
         this._calculatedParam = p;
-        this.calculatedParameterHeader = CalculatorResults.paramLabel(this._calculatedParam, true);
+        this.updateCalculatedParameterHeader();
+    }
+
+    public updateCalculatedParameterHeader() {
+        if (this._calculatedParam !== undefined) {
+            this._calculatedParameterHeader = CalculatorResults.paramLabel(this._calculatedParam, true);
+        }
+    }
+
+    public get calculatedParameterHeader(): string {
+        return this._calculatedParameterHeader;
     }
 
     public get hasResults(): boolean {