In this menu you can adjust the behavior of Reminders.
By default event reminders are shown the same way as other notifications (set in Menu > Settings > General > Notifications), but with this setting enabled you will be able to manage all your reminders in one place and easily Dismiss them or postpone them via the Snooze button.
This setting will ensure that the Reminders window pops up in the forefront so you don't miss any events or important reminders.
This setting dismissed reminders for events that have already passed, for example if you have an event set in the evening, you attend it before it pops up on your device, and then open eM Client next day - the reminder will not show up even though you did not dismiss it manually.
Set a default reminder time before the start of the event for all your calendars.
Set a default reminder time before the start of the tasks for all your task folders.