I get the following warning message when opening Gmail in IE8, stating that it looks like I have enabled Internet Explorer Compatibility View (for google.com), but I have not (and I have checked in settings).

Is it possible that Compatibility View has been enabled at the higher level (ie. downloaded database via Windows Update)?
Is Gmail just plain wrong?
Is this just Gmail subtly complaining that I'm using IE8 and not its own browser?
EDIT: As mentioned in my comment below, IE8 Compatibility View is indeed triggered (somehow).
IE=edge(so that should not force CV) and I haven't set CV, yet the website is certainly in IE8 CV, which I can forcefully change in IE developer tools - but this is only temporary. Incidentally, it does display better when not in CV, so I can't see any reason why it would be set? – w3d Jul 25 '12 at 19:20