♻️ [hidden] --> ngIfElse

src/app/calculator/calculator.component.html

@@ -3,14 +3,16 @@
   <div class="card-body">
     <div class="p-2 center-block">
       <!-- FIELD & INDEX SELECTION PART -->
-      <div [hidden]="noFieldSelected()">
+      <div *ngIf="!noFieldSelected(); else noField">
         <p>
           {{ 'CALCULATOR.selectedField' | translate}} {{data.selectedFieldProperties?.['id_dpb'] ?? '?'}}
         </p>
       </div>
-      <div [hidden]="!noFieldSelected()">
-        <p class="p-1 text-info">{{ 'CALCULATOR.selectField' | translate}}</p>
-      </div>
+      <ng-template #noField>
+        <div>
+          <p class="p-1 text-info">{{ 'CALCULATOR.selectField' | translate}}</p>
+        </div>
+      </ng-template>
       <div>
         {{hsLanguageService.getTranslationIgnoreNonExisting('CALCULATOR', 'selectQuantiles', {quantileCount: calcService.quantileCount})}}:&emsp;
         <input type="range" min="2" max="10" step="1" [(ngModel)]="calcService.quantileCount">