Unfortunately I don't have my camera with me at the moment but tonight I will give it a try.
Oh, also, I emailed the Canon customer service and they said that full time manual focus only works after the focus has been locked.
But I'm still looking for how to get the shutter to release more reliably in general (I was in a dimly lit room sort of, at nighttime, with the ceiling light on and I photographed an object shape - not like a wall - and it still took a few tries even though it seemed good enough in the viewfinder)