Canon 60D changes f stop automatically in Manual Mode

I'm trying to figure out the Manual Mode here, on my Canon 60D. When I set the f stop to the desirable number and then zoom onto my object the camera automatically changes that f stop number for me..isn't the whole point of Manual to allow the user to set f stop, ISO, shutter etc?

Im so confused...

please help me out if you know how to make the camera stop changing the f stop automatically while shooting in manual.