Just letting you know that the quest helper likes to turn itself on and off. Also for the past two days I've had it set to off but it's still activated. It's quite annoying as it's a resource hog and I don't like having it on.
I thought I'd let you know that the letter T on your keyboard, when pressed, will turn the Quest Helper off and on. If you're accidentally hitting T, it would explain why this feature keeps appearing for you.
If you do not feel this is the case, -please- let us know the details by submitting a bug report at the bottom of the Help&Support page linked in the left menu.