ValueError thrown in TreeEditor with 2-dimension Array

With the following code:

```
import numpy as np
from traits.api import HasTraits, Array, List, self
from traitsui.api import View, Item, TreeEditor, TreeNode

class A(HasTraits):
a = Array

class B(HasTraits):
content = List
myself = self

def _content_default(self):
return [
A(a=np.arange(4)),
A(a=np.arange(20).reshape((4, 5)))
]

tree_editor = TreeEditor(
nodes=[
TreeNode(
node_for=[B],
children='content',
),
TreeNode(
node_for=[A],
children='',
),
])

view = View(Item('myself', editor=tree_editor, show_label=False))

B().configure_traits(view=view)
```
selecting the 2nd leaf with an array of shape (4, 5) throws 4 times (once per line):
```
Traceback (most recent call last):
File "/Users/yves/miniconda3/lib/python3.8/site-packages/traits/trait_notifiers.py", line 342, in __call__
self.handler(*args)
File "/Users/yves/miniconda3/lib/python3.8/site-packages/traitsui/editors/tuple_editor.py", line 195, in _field_changed
if new != value[index]:
ValueError: The truth value of an array with more than one element is ambiguous. Use a.any() or a.all()
```