#674 add dock type

src/app/shared/object-grid/grid-thumbnail/grid-thumbnail.component.ts

@@ -45,6 +45,9 @@ export class GridThumbnailComponent implements OnInit, OnChanges {
     this.checkThumbnail(this.thumbnail);
   }
 
+  /**
+   * If the old input is undefined and the new one is a bitsream then set src
+   */
   ngOnChanges(changes: SimpleChanges): void {
     if (
       !hasValue(changes.thumbnail.previousValue) &&