the short form (as far as I know) is "There is no way you can tell which of the objects in a container is currently active."
(Except by looking, that is, you cannot capture the info in any variable or so).
I have in my apps introduced a new colour scheme to at least make it easier visible: I have the tabs on top of a container box, in dark blue, with fat white labels. That makes it easier to spot which object is active.
