Visualization: optionally display the id of an an object

Assume that `obj.someList` is the list `[1,2]`. Then the following two lines are visualized the same way, you cannot tell of the object is replaced or modified:

```python
obj.someList = [1,2,3]
obj.someList.append(3)
```

One solution would be to display the id of an an object. But I'm open for other solutions, as long as it distinguishes the two lines above.