The 'Optimized for Mobile' button is not available to press in the Desktop Editor. The issue occurs on a Windows 11 (10.0.26100) 64-bit system with the app version 255.0.0.5.316 and build ID 1975958549936554. The device used is a GamingPC (CyberPowerPC) with 551733 kb of Unity allocated memory. The issue was encountered in the World Configuration category of the Desktop Editor, with a session ID of 07ac5beb-cade-427c-9dde-34af59f7dcc4 and a world ID of 889073964004774.