Watermarkedtextbox control in Silverlight 2

Today, when I was studying Silverlight, I couldn't find watermarkedtextbox from the toolbox. I found out this was the case after Google clicked it. on Microsoft's forum, I said this:

Watermarkedtextbox has been removed from Beta 2 because the development team plans to add a watermark attribute to the textbox, so there is no need to use this control, unfortunately, this attribute has not been added in Beta 2.

That is to say, the watermarkedtextbox control will not exist in the future, and it will be replaced by the watermark attribute.