title: Error in my P5.play Editor - Exchange Error: you can only add sprites to a group
body: <p>I'm doing a game where the user has to code using p5.play, so, I did an online editor as a first step, but, I'm having problems when I run the code:</p>
  
  <p>--> When I write the code and run in the first time, everything works fine.
  --> If I run the code for a second or more time (in the case to correct something), the code shows a lot of errors and finally appears: uncaught exception: Error: you can only add sprites to a group</p>
  
  <p>I thought the problem was because I wasn't using a localhost server, but it wasn't it.
  I think the problem is in the part of the preview frame, I need some way to delete the previous result in order to appear the new code, but I don't know how to make it.</p>
  
  <p>The entire code is this link:
  <a href="https://drive.google.com/open?id=1jRFmUKngpjwn6J2VFNqvkc3HuxoEmeAV" rel="nofollow noreferrer">https://drive.google.com/open?id=1jRFmUKngpjwn6J2VFNqvkc3HuxoEmeAV</a></p>