How can I make to a transparency button?

I want to a transparency button, so I set th retangle opacity is 0, then it is disappear response.

Is there a solution ?

Oops, this is an error that I thought I fixed (invisible things should still be clickable).

But if you just want an invisible clickable area you can modify the HitTestMode of a panel.

<Panel HitTestMode="LocalBounds">
    <Clicked>
       ....
    </Clicked>
</Panel>

The LocalBounds says the entire area of this panel is hittable, thus it can be Clicked. You’ll of course need to give a size to the panel, either stretched to the parent (the default), or with an explicit Width and Height.

Thanks all !

I solved to use fill color, just like that.