Explain the switch of context better

[gnunicorn]

"Select the other option" is really vage and people dont even find the thing to look for. Maybe a screenshoot would help?

[xMartin]

The issue refers to this text on page 1:

If you want to inspect the environment of a page shown in the
sandbox, you have to take an extra step. If you open a console on that
tab, and you type myMessage into it, it won't find that
variable. This is because the console is connected to the sandbox page
itself, not the page shown inside of it. At the top left of the console,
there is a control that says <top>. Click on
this and select the option with the name of the domain that is
shown in the address bar of the browser to connect the console to the
actual page we wrote.

I think we already improved it. Let's double-check if it's good enough.

[andi-dev]

I was just sitting next to a complete beginner who got entirely confused and stuck by that passage.
It was not clear to her what is meant by the newly introduced term "environment", and it was confusing that, when clicking on 'top' she was seeing two options with the "name of the domain shown in the address bat", "top" and "about:blank". When choosing "about:blank" the dropdown turned red, leaving the impression to have made a wrong choice.

Maybe we could at least mention the "about:blank"? I know its hard at this point to start introducing the concept of iframes...

[xMartin]

It's gonna be hard to find the right words for everybody. I also think screenshots could be more helpful.