diff --git a/lib/matplotlib/backend_bases.py b/lib/matplotlib/backend_bases.py
index 36ed3ec6f157..513e1fdde487 100644
--- a/lib/matplotlib/backend_bases.py
+++ b/lib/matplotlib/backend_bases.py
@@ -1980,7 +1980,6 @@ def idle_event(self, guiEvent=None):
         s = 'idle_event'
         event = IdleEvent(s, self, guiEvent=guiEvent)
         self.callbacks.process(s, event)
-        return True
 
     def grab_mouse(self, ax):
         """