[Roberdin]

I think that from the UI point of view if anything is "greyed out" it should be clear why - not everyone understands the concept of a multiplex. I do like the idea of being able to see what channels are watchable/recordable within the guide, but maybe the other channels should be selectable also. If you select a channel which is not available for watching/recording, maybe you could get a message (slightly tailored dependent on whether you want to watch or record):

"MediaPortal cannot watch this channel at the moment, because it is recording other channels. To view this channel, you must cancel one group of the recordings below:

On Hauppauge DVB-T Nova-T #1:
* blah blah on BBC One
* blah blah on BBC Two
Cancel these

On Hauppauge DVB-T Nova-T #2:
* Something fascinating on More 4
Cancel this

Skip recording"

Or,

"MediaPortal cannot record this channel at the moment, because it is recording or viewing other channels. To record from this channel, you must stop watching your current programme and cancel all of the recordings below:
..."

If you have more than one tuner, then the UI is going to break down into a bit of a mess; mentioning the name of the card is probably unnecessary. Perhaps the multiplex could be put there in its stead. But IMHO, it is important to tell the user why he cannot watch a certain programme so that he can make up his mind as to whether he would like to cancel a whole batch of recordings on one card, another programme on a second card, or perhaps neither. I think it is within the scope of MediaPortal to lead the user through this.