This usually means that the user mixed up our lowercase/uppercase naming convention; see https://github.com/facebook/react/pull/3429#issuecomment-85166440.

We could add a message like

> Warning: The tag <commentBox> is unrecognized in this browser. If you meant to render a React component, start its name with an uppercase letter.

We'd check this only once per tag and only in development mode.

}
      } else if (propKey === CHILDREN) {
        if (
          lastProp !== nextProp &&
          (typeof nextProp === 'string' || typeof nextProp === 'number')
        ) {
          (updatePayload = updatePayload || []).push(propKey, '' + nextProp);
        }
      } else if (propKey === SUPPRESS_CONTENT_EDITABLE_WARNING) {
        
      } else if (registrationNameModules.hasOwnProperty(propKey)) {
        if (nextProp) {
          
          ensureListeningTo(rootContainerElement, propKey);
        }
        if (!updatePayload && lastProp !== nextProp) {
          
          
          
          updatePayload = [];
        }
      } else {
        
        
        (updatePayload = updatePayload || []).push(propKey, nextProp);
      }
    }
    if (styleUpdates) {