Explain the double dollar sign in the into at step 7, and maybe elsewhere

At http://webix.com/quick-start/introduction.html#!/7, the $$ construct is used. This should be explained.

(Is there a documentation page explaining it already? I can’t search for it on the site.)

We will update the tutorials and guides to make them more clear, thanks for the offer.

It would of helped me too if an explanation for “$$” was given. It kind of comes out of no where for a new person. I spent “x” amount of time researching when I see someone on the Webix Team said it would get fixed over a year ago…