fix: initialize LocationEvent after button def

Stefan Mitic · Stefan Mitic · commit d99430e826dc · 2020-03-31T13:38:48.000-04:00
diff --git a/lib/matplotlib/backend_bases.py b/lib/matplotlib/backend_bases.py
@@ -1394,14 +1394,16 @@ def __init__(self, name, canvas, x, y, button=None, key=None,
         (*x*, *y*) in figure coords ((0, 0) = bottom left)
         button pressed None, 1, 2, 3, 'up', 'down'
         """
-        LocationEvent.__init__(self, name, canvas, x, y, guiEvent=guiEvent)
         if button in MouseButton.__members__.values():
             button = MouseButton(button)
         self.button = button
         self.key = key
         self.step = step
         self.dblclick = dblclick
 
+        LocationEvent.__init__(self, name, canvas, x, y, guiEvent=guiEvent)
+
+
     def __str__(self):
         return (f"{self.name}: "
                 f"xy=({self.x}, {self.y}) xydata=({self.xdata}, {self.ydata}) "
