There's a killer feature for both text and code.
I've seen it in: jedit, writemonkey and scrivener.
It's simply isolating a paragraph (text) or a scope (code). For example, in writemonkey ^F6 isolates a paragraph, and shift F6 isolates the markdown section. This is very good for focusing.
Jedit does the same for code, ie, functions or scope.
Is this possible in sublime?