Difference between "wnd" and "html" in selector for Chrome?

Using the old version of Studio 20.10.4 I created a selector for automating Chrome. It worked fine and started with “<html app=…”.
Now after using Studio 21.4.3 this selector fails. It turns out that if worked again after changing to “<wnd app=”.
So question is: Why the old selector does not work on the new Studio any more and whats the difference?

Hi @moenk

When we use Attach Window, we get a “<wnd app” selector.
When using an Attach Browser we get a “<html app” selector.

If we use the modern activity “Use Application/Browser”, it automatically gets the more appropriated selector based on the application that we are selecting.

Which of these activities are you using?