Snoop

https://github.com/snoopwpf · SnoopWpf.Snoop

Snoop is an open source WPF spying utility originally created by Pete Blois and is currently maintained by Bastian Schmidt.

A Windows Presentation Foundation (WPF) tool which allows you to spy/browse the visual tree of a running application (without the need for a debugger) and change properties, view triggers, set breakpoints on property changes and many more things.