Wait for one or the other element

[Kris]

To wait for an element to exist, you have to do this:

var element = app.FindName("element");
element.Wait.ForExists();

In my silverlight application, at some point I have to wait for either elementA to exist or elementB to exist. So I created two tasks that each wait for one of the elements to exist:

var waitForElementATask = Task.Factory.StartNew(() => WaitForElement("elementA"));
var waitForElementBTask = Task.Factory.StartNew(() => WaitForElement("elementB"));
Task.WaitAny(waitForElementATask ,waitForElementBTask);

with WaitForElement() being:

private void WaitForElement(string name)
{
   var element = app.FindName(name);
   element.Wait.ForExists();
}

I thought this would be a good way to find out which one of the two elements show up. However, when I run this code, neither element will ever be found, even though they do show up. 

Anybody has any ideas?