Currently, in 'Edit Mode', if two overlapping Elements are both set to HitTestVisible=False, then the top one is Hoverable and Clickable.
However, if only the overlapping Element is set to HitTestVisible=False, then the bottom Element is Hoverable and Clickable.

HitTestVisible should really only be an Runtime/Play Mode feature, and should not impact what users are able to click on and hover over in Edit Mode.

Video Attached.

Repro Steps:

1) Create a Studio Project containing a MainPage.xaml

2) Introduce two Grid Elements, side by side, within the Page's root Grid.

3) Introduce a 512x512 Button to the bottom-most Grid introduced in Step 2), and set the Button's HitTestVisible Property to 'False' in its Properties.

3) Set the top-most Grid's HitTestVisible Property to 'False'.

4) Hover over the Button on-Stage.
Observe how the Button can't be hovered, and instead, the top-most Grid is hovered and selectable.

5) Set the Button's HitTestVisible Property to 'True', then deselect it by clicking off the Stage.

6) Hover over the Button.

Observe how the Button is now hoverable and Selectable.

Expected Results: HitTestVisible should not apply during Edit Mode.
Expected Results: In Edit Mode, HitTestVisibility should be an absolute attribute, and the ability to hover over, or select an Element should not be dependent on that of an overlapping Element.