title: How can I make a single instance form (not application)?
body: <p>In my C# application I have an option dialog that can be opened from a menu command.</p>
  
  <p>I want to ensure that the option dialog have only one instance (user cannot open more than one option window at a given time) without making it modal.</p>
  
  <p>Also if the user already have this window opened, and he clicks in the menu item to open it again, the app just makes the already visible form became the top most window.</p>
  
  <p>Can anyone point me directions on how accomplish these tasks?</p>
  
  <p>Thank you very much.</p>