GraphicsView: Set a trnasparent background palette

pyqtgraph/widgets/GraphicsView.py

@@ -130,6 +130,11 @@ class GraphicsView(QtGui.QGraphicsView):
         self.scaleCenter = False  ## should scaling center around view center (True) or mouse click (False)
         self.clickAccepted = False
 
+        # Set a transparent background QPalette!
+        palette = self.palette()
+        palette.setColor(QtGui.QPalette.Background, QtCore.Qt.transparent)
+        self.setPalette(palette)
+
     def setAntialiasing(self, aa):
         """Enable or disable default antialiasing.
         Note that this will only affect items that do not specify their own antialiasing options."""