Currently, certain Templates include Elements named "PART [...]", whose precise names are relied upon to supply Element functionality.
Renaming these Elements from their default/expected name can cause the Element to lose certain pieces of its functionality.

We should therefore consider displaying an orange or blue warning toast notification to the user when they rename this Element to a new name which could cause this functional loss.
Perhaps something along the lines of:

Title: Part name removed
Description: [PART_[xxx]] required to maintain Element functionality.

Repro Steps:

1) Create a Studio Project featuring a MainPage.xaml
2) Introduce a Slider into the Root Grid
3) 'Play' the Page, and slide the Slider left and right by clicking and dragging on its thumb.

Observe how the Slider slides as expected.

3) Create a new Slider Template
This will open the Template in the Template Dummy Editor.

4) Rename the Element named 'PART_Track' to any different name.

5) 'Play' the Page, and slide the Slider Thumb left and right.

Observe how the Slider functionality is lost.

Expected Results: Users are warned of the destructive action of renaming a critical Template 'PART_' as to reduce the chance of functionality loss in an Element