What makes the chart "offline"?

[Ex Ovo Omnia]

I did not find any relevant information in documentation on this site. The question is about difference between those chart windows:

and about the property in those chart Properties:

I noticed, that if I change this property manually, nothing happens until I restart the terminal.

Another difference is, that in offline chart I cannot switch to other timeframe like this:

and I can see it does not update with Market window.

Could anyone explain me, what the option in the Properties is intended for? Does any one find it useful? And what for?