title: Call MessageBox from async thread with Form1 as parent
body: <p>After clicking <code>button1</code> placed on <code>form1</code>, program is checking if the new version is available (via internet), but doing this in the new thread (not to freeze the form during check).<br>
  When the new version is found or not, the appropriate <code>MessageBox</code> is shown, but it has no parent (because it was called from the thread, not directly from the <code>form1</code>).  </p>
  
  <p>How to make the <code>MessageBox</code> display with <code>form1</code> as a parent?</p>