diff --git a/examples/ExampleApp.py b/examples/ExampleApp.py
index 1175f264..458daf76 100644
--- a/examples/ExampleApp.py
+++ b/examples/ExampleApp.py
@@ -189,7 +189,7 @@ class PythonHighlighter(QSyntaxHighlighter):
     @property
     def styles(self):
         app = QtGui.QApplication.instance()
-        return DARK_STYLES if app.dark_mode else LIGHT_STYLES
+        return DARK_STYLES if app.property('darkMode') else LIGHT_STYLES
 
     def highlightBlock(self, text):
         """Apply syntax highlighting to the given block of text.
@@ -310,7 +310,7 @@ class ExampleLoader(QtGui.QMainWindow):
         self.ui.codeView.setCurrentCharFormat(f)
         # finally, override application automatic detection
         app = QtGui.QApplication.instance()
-        app.dark_mode = True
+        app.setProperty('darkMode', True)
 
     def updateTheme(self):
         self.hl = PythonHighlighter(self.ui.codeView.document())
diff --git a/examples/syntax.py b/examples/syntax.py
index 1079c128..2c547867 100644
--- a/examples/syntax.py
+++ b/examples/syntax.py
@@ -186,7 +186,7 @@ class PythonHighlighter(QSyntaxHighlighter):
     @property
     def styles(self):
         app = QtGui.QApplication.instance()
-        return DARK_STYLES if app.dark_mode else LIGHT_STYLES
+        return DARK_STYLES if app.property('darkMode') else LIGHT_STYLES
 
     def highlightBlock(self, text):
         """Apply syntax highlighting to the given block of text.
diff --git a/pyqtgraph/Qt.py b/pyqtgraph/Qt.py
index 91c4d1b0..492604a1 100644
--- a/pyqtgraph/Qt.py
+++ b/pyqtgraph/Qt.py
@@ -480,7 +480,7 @@ class App(QtGui.QApplication):
         else:
             # Qt5 has this as a str
             color = palette.base().color().name()
-        self.dark_mode = color.lower() != "#ffffff"
+        self.setProperty('darkMode', color.lower() != "#ffffff")
 
 QAPP = None
 def mkQApp(name=None):