title: Duplicating Child Window problem
body: <p>In my application I have a Submit button that does this:</p>
  
  <pre><code>private void Submit_button_Click(object sender, RoutedEventArgs e)
  {
      string variable = variable_textBox.Text;
      if (variable.Length &gt;= 1 &amp;&amp; variable.Length &lt;= 6)
      {
          //get some data from db
      }
      else
      {
          ChildWindow msg = new Msg("Some string");
          msg.Show();
      }
  }
  </code></pre>
  
  <p>Here is my problem:</p>
  
  <p>When I write a string so that the program goes to the else clause, a childWindow will appear (that is OK); but if I do this again, 2 childWindows will appear. For each click on Submit button, I get num of clicks childWindows.</p>
  
  <p>Can someone tell me why? I use the same ChildWindow in other places, and I have no problems...</p>