I agree. I know it keeps track of the last person viewed because it lists that in the Tree Overview and in the "find person" drop down menu. You should be able to choose your settings. I'd like the option to choose what shows up when a tree is first selected, such as: Pedigree/Family Group Sheet, Tree Overview (which I think used to be the default), Last Viewed Person, List of all people.
I know you can click the Tree Pages menu or the find person drop down menu once you've selected the tree, but it just seems more user-friendly to allow people to set this preference.