Hidden notes

I find that when I add notes to the staves, the note sounds but doesn't always appear. If I switch from window view to page view, it appears and then remains. Similarly if I'm using page view and the same thing happens, the notes appear when I switch to window view. I also have a problem with what my tutor calls hanging notes. For example, I may have a whole note and some quarter notes in a bar but Notation converts it to to 4 quarter notes tied together which is not as neat as the hanging note. I've tried many options but can't seem to find my way around this problem. I love Notation and am eager to solve these glitches!