The loading screen technically isn't part of the calculator's UI - Windows automatically shows a loading screen for all new (UWP) apps unless they explicitly opt out (and even then the OS will still show the loading screen if the app takes more than a second to load). The purpose of this is to keep the OS feeling responsive, since it allows it to bring up the window immediately (for UWP apps the OS shell is in charge of creating and managing apps' window frames, unlike Win32 where it's the apps' responsibility), rather than leaving the user staring at a screen with nothing happening for several seconds (and maybe thinking it's the OS's fault for being unresponsive)
Regardless of whether it is or isn't part of the calculator's UI, the presence of a loading screen for a calculator is a symptom of a deeply-rooted problem.
> The purpose of this is to keep the OS feeling responsive, since it allows it to bring up the window immediately, rather than leaving the user staring at a screen with nothing happening for several seconds
Wait, you only get one of those? As of about a month ago on my computer, launching calc.exe takes 5-6 seconds for anything to happen and I'm then greeted 1-2 seconds of a loading screen after the window appears.
I've taken to just leaving an IDLE shell open at this point.
