Variable opacity within a WPF application

My problem is:

I have a Canvas which covers part of my Window. The Opacity of the canvas is set to less than 1, i.e. I can view the controls under the Canvas. What I would like to do is place a control, any control, say a Button, on the canvas and not have that Button semitransparent. Is this possible using WPF?

From stackoverflow

• Try the alpha in the color of the canvas.

  Cheers

  Robert Höglund : Worked like a charm. Thanks!

  Artur Carvalho : Glad to help ;-)