message: DownloadScreenshotControls: componentWillUnmount
  This should solve the error:
  Warning: Can't perform a React state update on an unmounted component.
  This is a no-op, but it indicates a memory leak in your application.
  To fix, cancel all subscriptions and asynchronous tasks in the componentWillUnmount method.
diff: @@ -58,6 +58,7 @@ export class DownloadScreenshotControls extends PluginUIComponent<{ close: () =>
  }
  componentWillUnmount() {
  + super.componentWillUnmount();
  this.setState({ imageData: void 0 });
  }
  