Merge pull request matplotlib#21530 from QuLogic/gtk-interrupt

Fix interrupting GTK on plain Python

Author: tacaswell

lib/matplotlib/backends/_backend_gtk.py

@@ -169,6 +169,13 @@ def mainloop():
 
         try:
             _application.run()  # Quits when all added windows close.
+        except KeyboardInterrupt:
+            # Ensure all windows can process their close event from
+            # _shutdown_application.
+            context = GLib.MainContext.default()
+            while context.pending():
+                context.iteration(True)
+            raise
         finally:
             # Running after quit is undefined, so create a new one next time.
             _application = None