Currently, when a Shape is used as a Clipping Mask, and applied to another Element, the 'Clip' Property displays an expander arrow to in theory, reveal more sub-properties.
However, when the expander arrow is clicked, the arrow simply disappears from the Properties Panel.

See attached video at the 0:40s mark.

Repro Steps:

1) Gather a PNG image of your choice, and place it in the Directory you will be working in for the rest of the repro steps.

2) Create a Studio in the Directory of Step 1), featuring a MainPage.xaml

3) Introduce an Image Element to the Stage, and set it to display the PNG prepared in Step 1).

4) introduce a CornerBox or Gear Shape to the Page's root Grid, adjacent to the Image Element introduce in Step 2).

5) In the Navigator, multiselect both the CornerBox/Gear Shape and the Image in the Navigator, then right-click on the CornerBox/Gear Shape, then from its 'Path' Context Menu category, select 'Make Clipping Path'.

At this point, the Shape is removed from the Navigator, leaving only the Image behind.

7) Save, then close and re-open MainPage.xaml, and select the Image Element once again.

8) Identify the Image's 'Clip' Property, and click the expander arrow directly to the left of the 'Clip' Property label.

Observe how the expander arrow disappears from view.

Expected Results: Property Expander Arrows are not displayed if the Property features no sub-properties or sub-options.