One thing that I have never fully understood was why the Enable Quick Launch menu item doesn’t actually disable the quick launch menu in any master pages other than the default.master (To find this menu click Site Actions > Site Settings > Modify All Site Settings > Tree View). Yesterday, my buddy Nik Molnar helped me track it down through some creative sleuthing on his part. Turns out the key is this tag from default.master: Microsoft’s BlueBand.master omits this tag, as well as many of the minimal publishing master pages that are available from the community. Without this tag surrounding the quick launch code, SharePoint cannot hide it via that Site Settings menu item. To add one, simply surround your with the completed tag.