solidworks 2012 sp3 - quadro fx1800

So I have this assembly drawing - I've imported Model Items cosmetic threads - however I am not sure I understand the different between high quality and draft quality display on the cosmetic threads.

When in the view I set High quality - all the dotted thread circles disappear - that's not supposed to happen right?

in draft mode they all show up - however they show even if they are not supposed to be in view (ie another part is covering it up or it's on the backside).

see the two attached images..

any ideas why high quality mode all thread circles disappear?

cheers,

Paul

high quality - no thread circle??? why                                                                      draft quality - circle, but shows even if hidden