🐛 [Story attachment] Opening outlink error for closeButton being null

extensions/amp-story-page-attachment/0.1/amp-story-page-attachment.js

@@ -559,6 +559,10 @@ export class AmpStoryPageAttachment extends DraggableDrawer {
     const closeButton = this.headerEl.querySelector(
       '.i-amphtml-story-page-attachment-close-button'
     );
+    // If attachment is outlink, there is no close button.
+    if (!closeButton) {
+      return;
+    }
     this.mutateElement(() => {
       if (isActive) {
         closeButton.removeAttribute('tabindex');