live visual tree

Debug > Windows > Live Visual Tree

Toggle between showing all WinUI XAML or just XAML you have written:

Show all elements in the MainWindow:

The numbers indicate how many children (direct and indirect) each element contains:

Click to enable a toolbar that floats over the app UI:

Select Element—select an element in UI and it will be selected in Live Visual Tree:

Click brackets to navigate to this element:

inspecting properties at runtime with live property explorer

Live Property Explorer always shows the properties of the element selected in the Live Visual Tree:

This Padding property is crossed out because it is set by a more specific Style.

Changes made to values in Live Property Explorer do not persist.