Hey, so the fact that you had trouble replicating it ate at my brain, and lead me to try starting a new blank project, only adding in VisuCore, your CraftCore and CraftMZ, all at their defaults. I still got the same window break. But then I tried dropping VisuCore in your test demo - and it works fine! So I spent the last day or so slowly copying chunks of my project into your Craft Demo, and as of a few moments ago I have the entirety of it transcribed and seemingly working fine. All the same plugins, maps. events, settings (that I'm aware of), everything. And behold:
I know this isn't a super ideal solution in the grand scheme of things, but I wanted to update you in case it might help narrow down where the problem was occurring if you still wanted to check it out, but I'm fine with calling this a fix.
I've really appreciated your time, Ramza. Thank you.