title: What is the least intrusive way to display WPF tooltip on focus?
body: <p>What is the minimum number of steps required to display a tooltip when the following control gets focus?</p>
  
  <pre><code>&lt;TextBox ToolTip="Hello there!" ... /&gt;
  </code></pre>
  
  <p>I tried the following in GotFocus</p>
  
  <pre><code>    private void ..._GotFocus(object sender, RoutedEventArgs e) {
          var element = (FrameworkElement)sender;
          var tooltip = element.ToolTip;
          if (!(tooltip is ToolTip)) {
              tooltip = new ToolTip { Content = tooltip };
              element.ToolTip = tooltip;
          }
  
          ((ToolTip)tooltip).IsOpen = true;
      }
  </code></pre>
  
  <p>However, it seems to ignore the <code>ToolTipService.Placement</code> for this control and <code>SystemParameters.ToolTipPopupAnimationKey</code> set up level higher.</p>
  
  <p>How can I make it work and honor all settings that generally work for tooltips (except the timing, obviously)?</p>