Résolution bug du bouton "XY / Histogramme" sous les graphiques

src/app/components/generic-select/generic-select.component.html

-<div class="btn-group" dropdown (selected)="onSelect($event)">
+<div class="btn-group" dropdown (click)="onSelect($event)">
     <button dropdownToggle class="btn btn-primary dropdown-toggle waves-light my-1" type="button" mdbRippleRadius>
         {{ currentLabel }}
     </button>

src/app/components/generic-select/generic-select.component.ts

@@ -30,7 +30,7 @@ export abstract class GenericSelectComponent<T> {
      */
     public onSelect(event: any) {
         const val = event.target.value;
-        if (val) {
+        if (val !== undefined && val !== "") { // might be 0; opening the menu returns ""
             this.selectedValue = val;
             this._currentLabel = this.selectedLabel;
         }