Thank you for your post.
You may be able to incorporate the Get(ActiveLayoutObjectName) or the Get(LayoutObjectAttribute) with "is active, "has focus" or "contains focus". It should be possible to use either of these functions in a calculation to determine whether a PopOver is active or not.
I hope this information is of use!
As far as I can see, popovers never have focus and are never the active object (or at least I've never managed to have get(layoutObjectAttribute) report a change in state between open and closed.
I guess this makes sense, as popovers are no more 'selectable' than a header or footer part. The button part of the popover can be active and have focus, but that's not much use if the popover is opened by script.
'Contains focus' would be useful if the user was expected to click in a field on the popover, but what if the popover only contains non-editable fields (i.e. not enterable in browse mode).
This is for an iPad layout -- swapping between portrait and landscape versions of a layout. As you are changing layout, in need to know which popover was open, so that I can open the same popover on the other layout.