title: Check if class has been instantiated
body: <p>In my current program I have a main window and a secondary window that pops up when a button is pressed. If the secondary window is currently shown but doesn't have focus the button will instead bring it to focus.</p>
  
  <p>At this time I am creating a new instance of the secondary window as the main window loads and simply checking its status with SubWindow.IsDisposed and SubWindow.CanFocus</p>
  
  <p>I have found that if I do not create a new instance at the beginning SubWindow.IsDisposed throws an exception. As long as I'd previously created an instance of SubWindow the check runs fine.</p>
  
  <p>My question-  The current version works fine but is there a better way of doing this? It is not a huge concern, but it feels like it'd be better to be able to check for existence without having to guarantee that it has existed at least once before.</p>