It would be really nice the possibility of setting a Z or Baseline property in overlays. So that you can show them behind characters or objects.
This has been suggested approximately infinity billion times before, however I'd still like to step in and show my support for the suggestion. :-*
Yes, either an extension of Overlay or some new generic type of dynamically created room independent object that could be freely set to obey/ignore baselines and walkbehinds would be greatly appreciated. It would especially be a huge help in module scripting to avoid the end user having to create dummy characters or whatnot.