Rewind of what you're watching is great, but I wondered what actions will "reset the rewind buffer"? Obviously changing channel is one thing that resets it, but what about hitting the TV guide etc ?

Why I ask is that I clicked the digital-text button and later tried rewinding, but to my surprise it only rewound as far as the point I'd hit TEXT :-( I suspect it may be because TEXT is on a different channel? (even though my prog sound continues in background)