I'm having issues with my dialogs' DateTime entries, using the Date field.
Only because Magnolia CMS tries to calculate relevant date-time to display according to your local TimeZone (vs the TimeZone it was entered in). By the way, that calculation is black magic (done using vaadin in their proprietary implementation I believe).
Anyhow, I wonder is there is a way to disable that TimeZone feature.
Many events are only "physical" events (they can't be attended online), so there is no point in displaying them according to other TimeZones anyway.
Example of issue this TimeZone feature has: jira.magnolia-cms.com/browse/MGNLUI-4014 and Magnolia CMS DateFieldDefinition issue with Daylight saving time change
Actually there is point of showing them in local timezones when you have distributed teams working in different timezones.
Anyway the issue you mention is scheduled to be fixed rather soon (AFAIK) and it will not affect anyone until next daylight saving change which is still couple months.
But to answer your question: If you don't want Magnolia to calculate the time zone for you, you can just set it for your user directly in user settings and then that timezone will be always used for you.
Hope that helps.