use empty-container deletion of Container class

buki.py

@@ -15,6 +15,8 @@ class Object:
     def delete(self):
         if self.parent is not None:
             self.parent.remove(self)
+        else:
+            print(self, "has no parent")
 
     def __repr__(self):
         return repr(self.layout)
@@ -55,9 +57,9 @@ class Container(Object):
         obj.parent = None
         self.children.remove(obj)
         self.layout.children.remove(obj.layout)
-#        if not self.children:
-#            print("Delete emptied container")
-#            self.delete()
+        if not self.children:
+            print("Delete emptied container", self)
+            self.delete()
 
     def delete(self):
         for obj in self.children:

director.py

@@ -77,9 +77,6 @@ class Director:
         self.updates.remove(a.update)
         print("Remove plot")
         a.container.remove(a.plt)
-        if not a.container:
-            print("Remove emptied container")
-            self.plot_container.remove(a.container)