Fix stopping of Tk timers from with timer callback.

anntzer · anntzer · commit bc7a9932752b · 2017-07-25T13:15:17.000-07:00
diff --git a/lib/matplotlib/backends/backend_tkagg.py b/lib/matplotlib/backends/backend_tkagg.py
@@ -94,8 +94,10 @@ def _on_timer(self):
         TimerBase._on_timer(self)
 
         # Tk after() is only a single shot, so we need to add code here to
-        # reset the timer if we're not operating in single shot mode.
-        if not self._single and len(self.callbacks) > 0:
+        # reset the timer if we're not operating in single shot mode.  However,
+        # if _timer is None, this means that _timer_stop has been called; so
+        # don't recreate the timer in that case.
+        if not self._single and self._timer:
             self._timer = self.parent.after(self._interval, self._on_timer)
         else:
             self._timer = None
