I find the editor in my head doesn't work for grammatical and spelling issues, but content is where it excels. I may not remember what a past participle is or how it's to be used, but I can usually come up with justifications for the use of most any word, or find a replacement, or build a world up from scratch. The only issue with that is, is that I have a constant running dialog in my head gibbering stories, characterizations, what if's, how's, why's and possibilities no matter how much I need the sleep. Like say, right now....It's Sat at 8am, and I've been up since 4am Friday mornin'....