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.

for (styleName in nextProp) {
            if (
              nextProp.hasOwnProperty(styleName) &&
              lastProp[styleName] !== nextProp[styleName]
            ) {
              if (!styleUpdates) {
                styleUpdates = {};
              }
              styleUpdates[styleName] = nextProp[styleName];
            }
          }
        } else {
          
          if (!styleUpdates) {
            if (!updatePayload) {
              updatePayload = [];
            }
            updatePayload.push(propKey, styleUpdates);
          }
          styleUpdates = nextProp;
        }
      } else if (propKey === DANGEROUSLY_SET_INNER_HTML) {
        var nextHtml = nextProp ? nextProp[HTML] : undefined;
        var lastHtml = lastProp ? lastProp[HTML] : undefined;
        if (nextHtml != null) {
          if (lastHtml !== nextHtml) {
            (updatePayload = updatePayload || []).push(propKey, '' + nextHtml);
          }
        } else {