Adjust scroll when statuses above the current scroll position are deleted

app/javascript/flavours/glitch/components/status.js

@@ -242,6 +242,15 @@ export default class Status extends ImmutablePureComponent {
     }
   }
 
+  componentWillUnmount() {
+    if (this.node && this.props.getScrollPosition) {
+      const position = this.props.getScrollPosition();
+      if (position !== null && this.node.offsetTop < position.top) {
+         requestAnimationFrame(() => { this.props.updateScrollBottom(position.height - position.top); });
+      }
+    }
+  }
+
   //  `setCollapsed()` sets the value of `isCollapsed` in our state, that is,
   //  whether the toot is collapsed or not.