Angular Material Mat-Menu

I am using Angular 8 with Angular Material and want to create a pop-up for a vertical dot menu which would look something like this image(corresponding html added below):

enter image description here

<div>
    <a aria-expanded="false" aria-haspopup="true" class="dropdown-toggle overflow-menu-toggle" data-flip="false" data-toggle="dropdown" href="#" id="dropdownOverflowMenu_v" role="button"><i class="material-icons">more_vert</i></a>
    <div aria-labelledby="dropdownOverflowMenu_v" class="dropdown-menu overflow-menu overflow-menu--vertical dropdown-menu-right dropright">
        <button class="dropdown-item"><i class="material-icons">email</i> Message </button>
        <button class="dropdown-item"><i class="material-icons">vertical_align_bottom</i> Download </button>
        <button class="dropdown-item"><i class="material-icons">edit</i> Edit </button>
        <button class="dropdown-item"><i class="material-icons">delete</i> Delete </button></div>
</div>

With Angular Material, I’ve managed to create the below pop-up(corresponding html added below) but the not able to get the top triangle like extended part(like highlighted in the above image)

enter image description here

<mat-menu #actionmenu="matMenu" class="actionMenu">
                  <mat-list>
                    <div *ngIf="item.isEditable">
                      <div mat-subheader><b>ACTIONS</b></div>
                      <mat-list-item>
                        <button mat-flat-button class="p-0" (click)="onEdit(item)">
                          <i class="material-icons">edit</i>
                          Edit
                        </button>
                      </mat-list-item>
                      <mat-list-item>
                        <button mat-flat-button class="p-0" (click)="onDelete(item)">
                          <i class="material-icons">delete</i>
                          Delete
                        </button>
                      </mat-list-item>
                    </div>
                  </mat-list>
                </mat-menu>

Can you please help with this?

Source: Angular Material Quesions