### Website or app

google.com

### Repro steps

This started after last update 4.20.0
![image](https://user-images.githubusercontent.com/11052469/137713404-e6702959-7870-46a6-8566-4cfe61d25309.png)
![image](https://user-images.githubusercontent.com/11052469/137713464-c5e478d2-4e9e-4ee4-abdf-83d23c04704b.png)


### How often does this bug happen?

Every time

### DevTools package (automated)

_No response_

### DevTools version (automated)

_No response_

### Error message (automated)

_No response_

### Error call stack (automated)

_No response_

### Error component stack (automated)

_No response_

### GitHub query string (automated)

_No response_
{
          source: 'react-devtools-bridge',
          payload: {event, payload},
        },
        '*',
        transferable,
      );
    },
  });
  const agent = new Agent(bridge);
  agent.addListener('shutdown', () => {
    
    
    hook.emit('shutdown');
  });
  initBackend(hook, agent, window);
  
  
  bridge.send('extensionBackendInitialized');
  
  if (hook.resolveRNStyle) {
    setupNativeStyleEditor(
      bridge,
      agent,
      hook.resolveRNStyle,
      hook.nativeStyleEditorValidAttributes,
    );
  }
}