@Tuarua - yes, I am saying that the AIR window resizes all by itself when it loads the WebView on Windows only. The before & after pics are not different compiles. This doesn't occur on macOS.
Yes, I have other window handling/stage resize events, but I disabled them && this still occurs.
I assumed it was BIAD (b/c I'm a dork), but it happens on your example desktop project too with my windows machines. I'll be happy to provide you with a link to a GH repo with project where this occurs (if you'd like), but I believe if you mimic the display settings below, then you'll see it too.
The VM is Parallels Windows 10 running on Macbook Pro Mid 2015 Retina Display, 15-inch.
- Windows 10 VM Display Settings

The Windows Tablet is a Surface Pro 4
- Surface Pro 4 Display Settings

No, I don't use <requestedDisplayResolution>high</requestedDisplayResolution> in AIR manifest on Windows. Doing so will break the webView (see below) & its positioning relative to other parts of UI.
Windows <requestedDisplayResolution>high</requestedDisplayResolution>

I'd be happy to record & upload a video so you may see it in action.