chore(pivot-row): remove unwanted thumb when using header-row in pivot-row

Author: mddragnev

projects/igniteui-angular/src/lib/grids/pivot-grid/pivot-header-row.component.html

@@ -5,9 +5,8 @@
     <div class="igx-grid__tr" role="row" [style.width.px]="width">
 
         <ng-container *ngIf="!row">
-            <div #pivotContainer class="igx-grid__tr-action" [style.min-width.px] = "grid.pivotRowWidths" 
+            <div #pivotContainer class="igx-grid__tr-action" [style.min-width.px] = "grid.pivotRowWidths"
                 (pointerdown)="$event.preventDefault()">
-                
             </div>
         </ng-container>
 
@@ -58,4 +57,4 @@
     </div>
 </div>
 <!-- Header thumb area -->
-<div class="igx-grid-thead__thumb" [hidden]="!grid.hasVerticalScroll()" [style.width.px]="grid.scrollSize"></div>
+<div class="igx-grid-thead__thumb" [hidden]="row ? true : !grid.hasVerticalScroll()" [style.width.px]="grid.scrollSize"></div>