diff --git a/lib/matplotlib/_pylab_helpers.py b/lib/matplotlib/_pylab_helpers.py
index 26ba7a171244..27904dd84b6f 100644
--- a/lib/matplotlib/_pylab_helpers.py
+++ b/lib/matplotlib/_pylab_helpers.py
@@ -53,18 +53,17 @@ def destroy(cls, num):
         It is recommended to pass a manager instance, to avoid confusion when
         two managers share the same number.
         """
-        if all(hasattr(num, attr) for attr in ["num", "_cidgcf", "destroy"]):
+        if all(hasattr(num, attr) for attr in ["num", "destroy"]):
             manager = num
             if cls.figs.get(manager.num) is manager:
                 cls.figs.pop(manager.num)
-            else:
-                return
         else:
             try:
                 manager = cls.figs.pop(num)
             except KeyError:
                 return
-        manager.canvas.mpl_disconnect(manager._cidgcf)
+        if hasattr(manager, "_cidgcf"):
+            manager.canvas.mpl_disconnect(manager._cidgcf)
         manager.destroy()
         gc.collect(1)
 
diff --git a/lib/matplotlib/backend_bases.py b/lib/matplotlib/backend_bases.py
index fe8cc66913cc..816db303ff65 100644
--- a/lib/matplotlib/backend_bases.py
+++ b/lib/matplotlib/backend_bases.py
@@ -3294,8 +3294,8 @@ def _update_view(self):
 
     def configure_subplots(self, *args):
         plt = _safe_pyplot_import()
-        tool = plt.subplot_tool(self.canvas.figure)
-        tool.figure.canvas.manager.show()
+        self.subplot_tool = plt.subplot_tool(self.canvas.figure)
+        self.subplot_tool.figure.canvas.manager.show()
 
     def save_figure(self, *args):
         """Save the current figure."""
diff --git a/lib/matplotlib/backends/backend_nbagg.py b/lib/matplotlib/backends/backend_nbagg.py
index 9eb076d9ec44..b921aa0a1d6e 100644
--- a/lib/matplotlib/backends/backend_nbagg.py
+++ b/lib/matplotlib/backends/backend_nbagg.py
@@ -231,7 +231,12 @@ def new_figure_manager_given_figure(num, figure):
         if is_interactive():
             manager.show()
             figure.canvas.draw_idle()
-        canvas.mpl_connect('close_event', lambda event: Gcf.destroy(manager))
+
+        def destroy(event):
+            canvas.mpl_disconnect(cid)
+            Gcf.destroy(manager)
+
+        cid = canvas.mpl_connect('close_event', destroy)
         return manager
 
     @staticmethod
diff --git a/lib/matplotlib/pyplot.py b/lib/matplotlib/pyplot.py
index 18e1739cab6d..73e77f6f0174 100644
--- a/lib/matplotlib/pyplot.py
+++ b/lib/matplotlib/pyplot.py
@@ -1546,7 +1546,8 @@ def subplot_tool(targetfig=None):
     """
     Launch a subplot tool window for a figure.
 
-    A `matplotlib.widgets.SubplotTool` instance is returned.
+    A `matplotlib.widgets.SubplotTool` instance is returned. You must maintain
+    a reference to the instance to keep the associated callbacks alive.
     """
     if targetfig is None:
         targetfig = gcf()