From 66d89433170ada9ed5a9ac0b14afacf2d7dbefca Mon Sep 17 00:00:00 2001
From: Ogi <ognyan.moore@gmail.com>
Date: Mon, 8 Jun 2020 21:36:09 -0700
Subject: [PATCH] PlotItem doesn't add item if already there

---
 pyqtgraph/graphicsItems/PlotItem/PlotItem.py | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/pyqtgraph/graphicsItems/PlotItem/PlotItem.py b/pyqtgraph/graphicsItems/PlotItem/PlotItem.py
index c61a35b2..79d59235 100644
--- a/pyqtgraph/graphicsItems/PlotItem/PlotItem.py
+++ b/pyqtgraph/graphicsItems/PlotItem/PlotItem.py
@@ -1,5 +1,6 @@
 # -*- coding: utf-8 -*-
 import sys
+import warnings
 import weakref
 import numpy as np
 import os
@@ -514,6 +515,9 @@ class PlotItem(GraphicsWidget):
         If the item has plot data (PlotDataItem, PlotCurveItem, ScatterPlotItem), it may
         be included in analysis performed by the PlotItem.
         """
+        if item in self.items:
+            warnings.warn('Item already added to PlotItem, ignoring.')
+            return
         self.items.append(item)
         vbargs = {}
         if 'ignoreBounds' in kargs: