title: Show Tooltip at specific control position via code
body: <p>I have a textBox that should display a tooltip with a explanation when the user types something wrong.</p>
  
  <p>But i'm not able to put the tooltip in the correct position.</p>
  
  <p>My text Box is inside a groupBox and a TabControl. I tried this:</p>
  
  <p><code>Point locationOnForm = new Point(this.Left + tabCon.Left + gbDocs.Left + tbKey.Left, this.Top + tabCon.Top + gbDocs.Top + tbKey.Top);</code></p>
  
  <p><code>tooltipError.Show("Test", this, locationOnForm , 3000);</code></p>
  
  <p>But the position is always nearby, never in the right spot.</p>