Nikolai Mavrenkov already created a good description of the problem on Stack Overflow: http://stackoverflow.com/questions/36893449/textarea-placeholder-isnt-shown-in-ie-11-being-rendered-using-react

I just can confirm it breaks in IE11, but works in IE10 (and other browsers) with React v15.0.2.

this.updateTextContent('' + nextContent);
        if (__DEV__) {
          setAndValidateContentChildDev.call(this, nextContent);
        }
      }
    } else if (nextHtml != null) {
      if (lastHtml !== nextHtml) {
        this.updateMarkup('' + nextHtml);
      }
      if (__DEV__) {
        ReactInstrumentation.debugTool.onSetChildren(this._debugID, []);
      }
    } else if (nextChildren != null) {
      if (__DEV__) {
        setAndValidateContentChildDev.call(this, null);
      }
      this.updateChildren(nextChildren, transaction, context);
    }
  },
  getHostNode: function() {
    return getNode(this);
  },
  /**
   * Destroys all event registrations for this instance. Does not remove from
   * the DOM. That must be done by the parent.
   *
   * @internal
   */
  unmountComponent: function(safely, skipLifecycle) {
    switch (this._tag) {