Created attachment 143689 [details] The spinbox SUMMARY See the screenshot; when the systemwide default is set to 12-hour time, most things in Kalendar use the 12-hour, but the spinboxes on the calendar event creator use 24-hour time. STEPS TO REPRODUCE 1. Set system default to 12-hour 2. Go to the event creation window and select time. OBSERVED RESULT The spinboxes has hours in 24-hour format EXPECTED RESULT The system default, that is used everywhere else, should be used SOFTWARE/OS VERSIONS Operating System: KDE neon 5.23 KDE Plasma Version: 5.23.3 KDE Frameworks Version: 5.88.0 Qt Version: 5.15.3 Kernel Version: 5.11.0-40-generic (64-bit) Graphics Platform: X11 Processors: 4 × Intel® Core™ i5-7200U CPU @ 2.50GHz Memory: 7.5 GiB of RAM Graphics Processor: Mesa Intel® HD Graphics 620 ADDITIONAL INFORMATION none