Uncaught TypeError: Cannot read property 'position' of undefined

I learn the usage from the example https://github.com/gaearon/redux-devtools/tree/next/examples/counter :

DevTools = createDevTools(
  <DockMonitor toggleVisibilityKey='H' changePositionKey='Q'>
    <LogMonitor />
  </DockMonitor>
)

ReactDOM.render(
  <div>
    <Provider store={store}>
      <div>
        <App />
        <DevTools />
      </div>
    </Provider>
  </div>
  document.getElementById('app')
)

Then DockMonitor throw an Error Uncaught TypeError: Cannot read property 'position' of undefined, I found it caused by the code https://github.com/gaearon/redux-devtools-dock-monitor/blob/master/src/DockMonitor.js#L74, because props.monitorState is not exist.

Is any step I missed?

[newoga]

Hey @bolasblack,

This may or may not be your issue, but I also just ran into this same error and it was because I forgot to add DevTools.instrument() to my store enhancing function.

See this example

[torgeir]

I also hit this, calling require('dev-tools').instrument() directly, and not the .instrument() on my createDevTools(..)-created dev-tools.