Still having trouble with the wacky window?
1. Press Windows+R.
2. Type regedit.exe.
3. Accept the administrator prompt.
4. In the search bar, copy: Computer\HKEY_CURRENT_USER\SOFTWARE\LJ LephemStar or navigate to it.
5. Do not click on 'Keys' or resembling to a folder.
6. Delete everything with Screenmanager.
This will not delete your data! Only the screen resolution will be reset.
7. You're done! Open the game, and everything should be alright.
Alternatively, if anyone has experience in tech, you could make a registry editor file that deletes Screenmanager and then run it each time the window glitches.