I'm not sure if anybody mention this but GDrive actually does not download documents to your local machine. It just adds a json document pointing to file to edit.
This seems to only be the case with "Google" document formats (Google document, Google spreadsheet, etc). Every other file type seems to sync local files appropriately.
There is an option in settings drop down from top left of the homepage od docs. Also the offline url is https://docs.google.com/offline. But you need to set up offline first from the menu i wrote about above.
So what is point of GDrive?