According to the normal way the Foundry map tool works, newer objects normally are "above" older ones, even if the older ones have an equal or greater "Y" value on the 2D map where the objects are manually placed.
However, while making a city - a city that already has a lot of objects - I've noticed that when I try to place a new object (whether it be a buidling, detail object, or even a complete mob), it now appears below all the already established objects - inlcuding platforms (that I plan to use for streets and such), and buildings. Which makes it very, very tough to look at how a new object (or series of new objects) relate to already established stuff without going to test mode, logging out, adjusting, going to test mode again, etc.)
I know this has happened intermittently before, but now it seems consistent. Has anyone else encountered this, and if so, is there any way to fix this?