message: Improving photo rendering during ligthbox navigation (preview mode)
diff: @@ -212,13 +212,22 @@ export class GalleryGridComponent implements OnChanges, OnInit, AfterViewInit, O
  }
  }
  + /**
  + * Makes sure that the photo with the given mediaString is visible on the screen
  + * @param mediaStringId
  + * @private
  + */
  private renderUpToMedia(mediaStringId: string): void {
  const index = this.media.findIndex((p): boolean => this.queryService.getMediaStringId(p) === mediaStringId);
  if (index === -1) {
  this.router.navigate([], {queryParams: this.queryService.getParams()});
  return;
  }
  - while (this.renderedPhotoIndex < index && this.renderARow()) {
  + // Make sure that at leas one more photo is rendered
  + // It is possible that only the last few pixels of a photo is visible,
  + // so not required to render more, but the scrollbar does not trigger more photos to render
  + // (on ligthbox navigation)
  + while (this.renderedPhotoIndex - 1 < (index + 1) && this.renderARow() !== null) {
  }
  }
  @@ -265,6 +274,8 @@ export class GalleryGridComponent implements OnChanges, OnInit, AfterViewInit, O
  }
  + // TODO: This is deprecated,
  + // we do not post update galleries anymore since the preview member in the DriectoryDTO
  private mergeNewPhotos(): void {
  // merge new data with old one
  let lastSameIndex = 0;
  