From 3240f7a435e6e744491a8f7a9544bc9d1f4e44f4 Mon Sep 17 00:00:00 2001
From: Luke Campagnola <luke.campagnola@gmail.com>
Date: Fri, 23 Feb 2018 17:40:36 -0800
Subject: [PATCH] fix qapp storage bug

---
 pyqtgraph/Qt.py | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/pyqtgraph/Qt.py b/pyqtgraph/Qt.py
index ad2a8007..8c0041df 100644
--- a/pyqtgraph/Qt.py
+++ b/pyqtgraph/Qt.py
@@ -274,8 +274,9 @@ if m is not None and list(map(int, m.groups())) < versionReq:
     raise Exception('pyqtgraph requires Qt version >= %d.%d  (your version is %s)' % (versionReq[0], versionReq[1], QtVersion))
 
 
+QAPP = None
 def mkQApp():
-    app = QtGui.QApplication.instance()
-    if app is None:
-        app = QtGui.QApplication([])
-    return app
+    global QAPP
+    if QtGui.QApplication.instance() is None:
+        QAPP = QtGui.QApplication([])
+    return QAPP