Expander

Using a GroupBox inside the expander (as a sample in my app); this however shows open/close. It uses a opacity fade to come in/out. Does this match up with the current style?

![expander_sample](https://f.cloud.github.com/assets/677341/1648224/1dd2ea62-597f-11e3-9748-b773a3e71a64.jpg)