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.

return styleStore.display;
        },
        set display(v) {
          styleStore.display = v;
        },
        get fontFamily() {
          return styleStore.fontFamily;
        },
        set fontFamily(v) {
          styleStore.fontFamily = v;
        },
        get lineHeight() {
          return styleStore.lineHeight;
        },
        set lineHeight(v) {
          styleStore.lineHeight = v;
        },
      };
      var container = document.createElement('div');
      ReactDOM.render(<div style={styles} />, container);
      var stubStyle = container.firstChild.style;
      stubStyle.display = styles.display;
      stubStyle.fontFamily = styles.fontFamily;
      styles.display = 'block';
      ReactDOM.render(<div style={styles} />, container);
      expect(stubStyle.display).toEqual('none');