Kodi add-on crashing on window.removeControl()

I'm developing a Kodi add-on that uses a custom overlay. It's almost completely working now, except for one runtime error I get every time I start a video, after reaching 5 seconds in the video ("Error Contents: Control does not exist in window"). Here's the code for addon.py below:

import xbmc, xbmcaddon, xbmcgui, os
ADDON = xbmcaddon.Addon()
addonpath = ADDON.getAddonInfo('path')

class OverlayBackground(object):
   def __init__(self):
      self.showing = False
      self.window = xbmcgui.Window()
      origin_x = 0
      origin_y = 0
      window_w = self.window.getWidth()
      window_h = self.window.getHeight()
      self._background = xbmcgui.ControlImage(origin_x, origin_y, window_w, window_h, os.path.join(addonpath,"resources","skins","default","media","background.png"))
   def show(self):
      self.showing=True
      self.window.addControl(self._background)
   def hide(self):
      self.showing=False
      self.window.removeControl(self._background)
   def _close(self):
      if self.showing:
         self.hide()
      else:
         pass
      try:
         self.window.clearProperties()
      except: pass

if (__name__ == '__main__'):
   monitor = xbmc.Monitor()
   while not monitor.abortRequested():
      if xbmc.Player().isPlaying():
         theOverlay = OverlayBackground()
         if(xbmc.Player().getTime() < 5):
            theOverlay.show()
         else:
            theOverlay.hide()
         xbmc.sleep(1000)

The error came from "self.window.removeControl(self._background)", as mentioned in this paste bin. It seems odd, because I'm sure that the control was added prior to running this command, so I'm not sure what's causing this command to crash the add-on.

I tried asking over in the Kodi forums for help, and was told that I need to get the ID of the player that I'm controlling (and linked to the documentation for Control), but I'm not sure how to implement that, even after researching the documentation extensively.

I would highly appreciate any clarification on this. Thank you so much in advance!

you need to check if the overlay already removed

   def show(self):
      if not self.showing:
          self.showing=True
          self.window.addControl(self._background)
   def hide(self):
      if self.showing:
          self.showing=False
          self.window.removeControl(self._background)