diff --git a/ui-ngx/src/app/shared/components/time/aggregation/grouping-interval-options.component.html b/ui-ngx/src/app/shared/components/time/aggregation/grouping-interval-options.component.html
index b93cd2cc96..9854427ba6 100644
--- a/ui-ngx/src/app/shared/components/time/aggregation/grouping-interval-options.component.html
+++ b/ui-ngx/src/app/shared/components/time/aggregation/grouping-interval-options.component.html
@@ -32,6 +32,7 @@
                   [subscriptSizing]="subscriptSizing" [appearance]="appearance">
     <mat-select formControlName="defaultAggInterval"
                 placeholder="{{ 'action.set' | translate }}">
+      <mat-option>--</mat-option>
       <mat-option *ngFor="let interval of selectedIntervals" [value]="interval.value">
         {{ interval.name | translate:interval.translateParams }}
       </mat-option>