Just found out this is a known issue with Qt. This is being tracked as a bug by the Qt developers:
https://bugreports.qt.io/browse/QTBUG-67699
There is also a report on the Windows Feedback Hub:
https://insider.windows.com/en-us/fb/?contextid=916&feedbackid=7cbd9062-fbac-4131-8cd0-c3a75d3b4638&form=1
Windows 10 with the Feedback Hub app is required to view this report.
According to the bugs, this is apparently due to the windows being created with the WS_POPUP flag.
https://bugreports.qt.io/browse/QTBUG-67699
There is also a report on the Windows Feedback Hub:
https://insider.windows.com/en-us/fb/?contextid=916&feedbackid=7cbd9062-fbac-4131-8cd0-c3a75d3b4638&form=1
Windows 10 with the Feedback Hub app is required to view this report.
According to the bugs, this is apparently due to the windows being created with the WS_POPUP flag.
