By the way Derek, does Altium now handle buses intelligently?
To be honest, I've not had a problem with Altium 14 with buses. I was/am suspecting the problem seen on your monitor was due to the video card ie an error in how you see it, not an error in how Altium handles it.
But having said that I have found that Altium does not always display the truth. It is important to view each layer in single layer mode before generating the gerbers (or sending the Altium file away for manufacturing) to ensure one layer does not hide something untoward below. Even though you can change the layer order, Altium does not always display the layer precedence as you would expect.
I first noticed this fault in Ver 6.9 it appears to be carried over to the current version. I was told in 2008 that it was my video card but I transferred the design to another computer (a laptop) & it was displayed with exactly the same error.
Protel 2.5 (1996 version) suffered a scrolling problem in full screen mode (in one direction only). This was still present in Altium 6.7 (2006 version) which is 10 years later! I was promised this was fixed in ver 6.7 so I paid AUD$3600 for the upgrade only to find that a "proper" full screen mode was no longer selectable. So, instead of Altium properly fixing the bug, they did away with the full screen mode (yes, I know it's still selectable in version 6.9 & ver 14 but you can no longer maximise your screen by removing all the toolbars & the Windows scroll bars like you can in ver 6.7).
So, what have I learnt?
1/ With Altium, what you see it not always what you will get;
2/ Altium sales people do not always tell you the truth;
3/ Altium can carry bugs through many versions (in my case 10 years).