QMenu: popup-menu does not render properly if opened on external monitor

To reproduce:

1. Compile the attached trivial example program on a Mac (I used a MacBook M2 Pro running Ventura 13.3, although I suspect the exact Mac used doesn't matter)
2. Attach a second monitor to the Mac, and in the MacOS "Display" settings, make sure that the second monitor is positioned "above" the default monitor in the virtual-monitor-layout (see first attached screenshot for an example)
3. Run the compiled trivial example program
4. Note that if you have the program's window on the primary monitor and click the "Click Me!" button, you get a context menu with 30 items in it, with the 15th item near the mouse pointer, as expected (see left-hand side of the second attached screenshot)
5. Now move the window "up" to the external monitor and click the "Click Me" button again.  Note that the context menu appears but it is empty (see right-hand side of the attached screenshot)

Expected behavior is that the context menu will correctly populate with the 30 data items regardless of what monitor the window is located in.