Interesting issue with Gmail.
I don't know if this is an Opera problem, or a browser sniffing problem.
If I load Gmail in standard view, with Opera identified as Opera, I'm just seeing a blank page. Upon setting Style to User Mode, it appears that Gmail is still trying to load stuff, and advises to switch to "basic HTML view". Of course, then I can see everything, and Gmail advises me to "Upgrade your browsr for faster, better Gmail".
If I identify as Firefox, Gmail still insists on basic HTML view. If I identify as IE, Gmail says it requires Activex controls to be enabled.
Hmmm… seems it's a browser sniffing issue.