Negative on any debug window in my 12.3.1. with that trick (though I didn't know about this before).
There are various ways to disable the debug window in Vaadin, possibly Automic now considers AE to be stable enough not to ship debug builds anymore? :D
Unfortunately, it's not as simple as it being disabled in web.xml, where one could re-enable it. There are various other ways, Java properties and I don't know where they'd go, and as per Google also a Maven option, which is probably issued at build time, which might mean we're possibly SOL.
Might toy around with the options later.