Hiding titles of filter categories when no filter exists

src/app/components/items-grid/items-grid.component.html

@@ -13,6 +13,7 @@
 </div>
 
 <mat-menu #filterMenu="matMenu" class="big-panel">
+	<ng-container *ngIf="this.genres.length > 0">
 		<h4><b>Genres</b></h4>
 		<mat-chip-list>
 			<!--suppress AngularInvalidExpressionResultType ('default' color is valid for mat-chip)-->
@@ -22,7 +23,9 @@
 				{{genre.name}}
 			</mat-chip>
 		</mat-chip-list>
+	</ng-container>
 
+	<ng-container *ngIf="this.studios.length > 0">
 		<br/>
 		<h4><b>Studios</b></h4>
 		<mat-chip-list>
@@ -33,6 +36,7 @@
 			{{studio.name}}
 			</mat-chip>
 		</mat-chip-list>
+	</ng-container>
 </mat-menu>
 
 <mat-menu #sortMenu="matMenu">