Timezone management

Hello, I have tried several calendar apps. Some do not manage timezones like others. Onecalendar correctly manages normal events. However, when it comes to all day events, the timezone lock option doesn't work. To be clear, i have an event starting à 23h30 on day n. There is an all day event and a normal event starting at the same time. I temporarily move to a +timezone (at least one timezone towards the east). Without the timezone lock options, both events appear on day n+1. With the timezone lock option, both events should begin on day n. With the timezone lock option in reality, only the normal event starts on the correct day, the all day event still starts the day after. Please solve this :'(