title: How to allow for multiple popups at once in WinRT?
body: <p>If you call the <code>ShowAsync</code> command on a <code>MessageDialog</code> object when another <code>MessageDialog</code> object has already been displayed to the user but not dismissed (i.e. you show a popup when another one is already up), an <code>UnauthorizedAccessException</code> is thrown. This can make things difficult when you have multiple threads attempting to alert the user at the same time.</p>
  
  <p>My current (stopgap) solution is merely to surround the <code>ShowAsync</code> call with a try/catch block and swallow the exception. This undesirably leads to the user missing out on subsequent notifications. The only other way around this that I can think of is to manually implement some sort of popup queue. This seems like an inordinate amount of work, however, considering other frameworks (like Windows Phone) do not have this issue and will merely display the popups one after another as the user dismisses them.</p>
  
  <p>Is there another way to solve this problem?</p>