title: Konva - clear layer but keep the background
body: <p>Im trying to clear the layer from every circle and line (remove it completely) but keep the image in the background.</p>
  
  <p>If I use <code>layer.clear()</code> it removes the image also.</p>
  
  <p><strong>Question</strong>: How to clear the layer but avoid removing the image?</p>
  
  <p><a href="https://codesandbox.io/s/sharp-night-t4vtt" rel="nofollow noreferrer">https://codesandbox.io/s/sharp-night-t4vtt</a></p>