Events for adding items to ObservableDictionary are not consistent

[abeham]

The following code fires ItemsAdded if element key was not present in the dictionary yet:

observableDict[key] = val;

whereas the following code fires ItemsAdded as well as PropertyChanged 4(!) times with "Item[]", "Keys", "Values", and "Count" as property names:

observableDict.Add(key, val);

Both ways should lead to the same events being fired.