I couldn't find anything obvious, I am gonna ask on slack

Edit: While there doesn't seem to be a world API for that, it was suggested that we find the active window ourselves by traversing submorphs starting at Project current world. It sounds a bit tedious, but shouldn't be too bad to implement. It'll probably come down to how reliable we can gather this information. Decoupling the specifics of the whitelisted windows and the search itself could also be difficult, good thing we only a spike this sprint :^)