[Dumyat]

Probably worth mentioning that the new Channel Group functionality has some slight differences to that of the default skin (Estuary). In Estuary, Channel Groups can only be accessed when the user scrolls 'UP' from the first item in the EPG. I personally found this behaviour to be a little annoying, particularly if you are near the bottom of a particular Channel Group and have to scroll all the way to the top of page. So in Amber you only to press the 'Back' button on your remote from anywhere on the EPG and you are you immediately taken to the Channel Groups. Of course if you are near the top of the EPG, you can still use the 'UP' option to access the Channel Groups as well. Basically, both options are available.
Also, in Estuary if a user wants to access the PVR sideblade settings, they have to scroll 'Left' to the very 1st Day shown in their EPG which will open the sideblade. Again, I found this behaviour to be a little tedious, so in Amber you only have to press the 'Back' button which will take you to the Channel Groups, then press 'UP' which opens the PVR sideblade settings. 
One final difference is when you scroll 'Right' on the Channel Groups and reach the last group you can actually continue to scroll 'Right' again and you will loop around to the 1st Channel Group, rather than having scroll 'Left' all the way back to the 1st Channel Group, which is what users have to do in Estuary.    
To Exit the EPG altogether, users now to press the 'Back' button twice (as the first click takes you to the Channel Groups). 
Hope this all makes sense....