message: Make the drop event propertly trigger inside the SnapDropContainer
diff: @@ -140,7 +140,9 @@ export class SnapDropContainer extends ThemeableElementBase {
  }
  private _handleDragOver(ev: DragEvent): void {
  + ev.preventDefault();
  ev.stopPropagation();
  +
  this._showDragCover(ev);
  }
  @@ -214,8 +216,8 @@ export class SnapDropContainer extends ThemeableElementBase {
  mimeType: mimeType,
  dropData: data
  };
  - const tabDropEvent = new CustomEvent(SnapDropContainer.EVENT_DROPPED, { bubbles: true, detail: detail });
  - this.dispatchEvent(tabDropEvent);
  + const customDropEvent = new CustomEvent(SnapDropContainer.EVENT_DROPPED, { bubbles: true, detail: detail });
  + this.dispatchEvent(customDropEvent);
  }
  }
  