Or are you are in "Theater View" and want to bring up the EPG guide without stopping the current playing TV show?
I believe this is the correct scenario. Well actually, he is in Display View watching TV, probably live or Time Shifted, and he probably got there from Theatre View, through the Guide. Then he presses the Guide button on the remote to see what else is on. But the process, and the setting I mention in the linked thread, works the same if you start playing something in Standard View, then press the Guide button, then want to get back to Display View again.
Brett can confirm.
Works great! But how do I get back to watching that channel? On WMC, I could scroll the cursor to the small live window and press "OK" to return it to fill screen.
If you have an MCE remote, just press the big green button and MC will toggle through recent displays, up to three I believe, and so you can get back to Display View. On my system, if I go from live TV to Guide, I only need one press of the big green button to get back to the TV channel playing.
If you don't have a remote with a big green button, then a button with the assigned command "Media Center" does the same thing.