For Elements that can be Data-Populated or Manually-Populated, there is some inconsistency in the method in which their default Templates are pre-populated.

For example:

The ListBox, the ListView, the ItemsControl, the ComboBox, the HeaderedItemsControl, the TreeView, and the StatusBar, all come pre-populated with a #-numbered dummy array of strings meant as placeholder for Data-driven content.

The TabControl, the Menu, and the ContextMenu on the other hand, each come prepopulated with their associated sub-Elements in the Navigator, destined for manual-adding of their contents.

This inconsistency can lead to difficulty applying lessons from one similar Control to another.

There is some debate as to whether Elements should be pre-readied for Data-Driven or Manually-placed sub-Elements, but its likely they should all follow the same pattern.

Repro Steps:

1) Create a Studio Project featuring a MainPage.xaml
2) Introduce all of the above-mentioned Elements into the RootGrid of the Page.
3) Observe how their default population method is not consistent between all of them.