Cannot show the "Repeat days' buttons" when I run the "alarms" example on Windows 10

[Richard L]

I'm new to Qt. I'm learning the official document Getting Started Programming with Qt Quick. When I run this example with give codes on my PC. The Main window does not show the "Repeat days" buttons. Please see following pictures. My OS is Windows10, Qt version is 6.9.0, Qt Creator version is 16.0.2. The codes can be found here. Please help me, thank you.