Backport PR #12707: Fix tk error when closing first pyplot figure (#12732)

meeseeksmachine · timhoffm · commit 1cad07e5ccf0 · 2018-11-04T09:01:12.000+01:00
diff --git a/lib/matplotlib/backends/_backend_tk.py b/lib/matplotlib/backends/_backend_tk.py
@@ -1034,4 +1034,6 @@ def trigger_manager_draw(manager):
 
     @staticmethod
     def mainloop():
-        Tk.mainloop()
+        managers = Gcf.get_all_fig_managers()
+        if managers:
+            managers[0].window.mainloop()
