Well, it's just that the whole new tab/new window thing and the autoresizing (which I personally hate) sound like my firefox update.
If you're running FF, you should be able to change the behaviour in the options. It's the 'Open New Pages in...' option. If you want them to open in the
same window (and tab), there's an option for that somewhere in the UserCP. The double clicking bit I'm not sure about.