wpf / silverlight textbox filter design -

I have a list that users can filter in several ways, two of which lend themselves to the combo boxes and two Needs to accept user input. For example, a text box allows the user to type in any part of the description of a list item, and will display only those items whose text is entered in the text.

This is a dialogue type 'picker' type window, so space is at a premium. I did not want a conventional label for the text box. Instead, when the dialog is first brought, the label ( I.e., "description") becomes grayed out, centered, and in the intersection. A tool tip might explain to the user how it is. When the user starts typing, the incorrect label disappears and the text entered is normal left-aligned text.

Is there any basic support for doing this kind of WFP / Silver? I think it can be a combination of styles and events. I did not want to invent any wheels which could be from there (I met Tartoise '"Log Lodge" window in particular, but I have seen it before).

Can anyone share the sample code for doing so? Or an alternative idea that saves space and simplifies the layout?

Cheers, Beryl

Kevin Moore's Infotextbox, which is a part of it, As I was watching, almost all this is also the 'watermark' (great name - if I had come to know it, I would know this) text box.