Studio shows Exit in the File menu on Windows

Objo Studio’s in-window File menu on Windows and Linux does not include a visible app-exit command. Windows users expect File > Exit at the bottom of a menu-bar File menu, with Alt+F4 handled by the OS rather than shown as an in-menu shortcut. Studio should add a platform-appropriate File menu command that uses the normal window-close flow so save prompts and active debug-session prompts still appear.