diff --git a/13_GUINext/code/button_only.py b/13_GUINext/code/button_only.py
index e6b0a8b..493496f 100644
--- a/13_GUINext/code/button_only.py
+++ b/13_GUINext/code/button_only.py
@@ -14,3 +14,4 @@ def __init__(self, root):
     root = Tk()
     SimpleWindow(root)
     root.mainloop()
+    root.destroy()
diff --git a/13_GUINext/code/grid_example.py b/13_GUINext/code/grid_example.py
index 4364db6..f23930d 100644
--- a/13_GUINext/code/grid_example.py
+++ b/13_GUINext/code/grid_example.py
@@ -17,3 +17,4 @@ def __init__(self, root):
     root = tk.Tk()
     GridWindow(root)
     root.mainloop()
+    root.destroy()
diff --git a/13_GUINext/code/iris_viz/src/gui.py b/13_GUINext/code/iris_viz/src/gui.py
index b837ac9..8c3fe5f 100644
--- a/13_GUINext/code/iris_viz/src/gui.py
+++ b/13_GUINext/code/iris_viz/src/gui.py
@@ -82,6 +82,7 @@ def init_controls(self):
 
         self._y_selection = tk.IntVar()
         self._y_selection.set(1)
+
         for row, label in enumerate(self.labels[:-1]):
             radio = tk.Radiobutton(self.frame_y, variable=self._y_selection,
                                    value=row, text=label,
diff --git a/13_GUINext/code/tree_example.py b/13_GUINext/code/tree_example.py
index 3843688..3ec00ce 100644
--- a/13_GUINext/code/tree_example.py
+++ b/13_GUINext/code/tree_example.py
@@ -23,3 +23,4 @@ def __init__(self, root):
     root = tk.Tk()
     TreeWindow(root)
     root.mainloop()
+    root.destroy()
diff --git a/13_GUINext/code/update_label.py b/13_GUINext/code/update_label.py
index 6dbf318..61fe5d7 100644
--- a/13_GUINext/code/update_label.py
+++ b/13_GUINext/code/update_label.py
@@ -22,3 +22,4 @@ def toggle(self):
     root = tk.Tk()
     ToggleWindow(root)
     root.mainloop()
+    root.destroy()