If you happen to do some WPF development you could have noticed that quite recently (I believe it was w/ Update 3) Visual Studio has added a small box at the top of your app to should you the available options for visual tree selection and manipulation.
It looks like this:
It gets trickier when you already use some other tool. I was using XamlSpy for a long time before this new feature was introduced and both tools occupy the same place on the window so was I see both tools overlay each other.
Fortunately there is a way to turn this damn helper off. Just use Live Visual Tree and uncheck the first icon. Even better you can turn it on/off during runtime. So you can decide whether you want this tool or not w/o the need of restarting your app.
The same can be achieved by unchecking the ‘Show runtime tool in application’ in the Debugging options as shown on the last screenshot.