We will use Zimbra mostly for the shared calendar options, so it doesn't matter much the docs are not in HTML version.
But thanks all for info, I wanted to know if it has some
really big drawbacks, since usual tasks like adding new calendar action works in both. It's very uncomfortable to have two different browsers opened, so I'll stick with Opera (mmorse: added a vote, thanks!) and HTML version, and in troubles use FF.
Btw I found why the AJAX mode seem too clumsy in FF, my gesture extension blocked all right-click menus, which is solved in
this thread.