Deleting something is no longer final
Delete an event and you now get a few seconds to take it back, with an Undo button on the confirmation.
Deleting used to be instant and permanent. Now it waits for you.
A grace period on every delete. When you delete an event, it disappears from your calendar straight away, but a message appears with an Undo button. Change your mind within a few seconds and the event comes back exactly as it was.
It covers the frightening one too. Deleting a whole repeating series, which could previously remove dozens of entries in one tap, is undoable in the same way. So is skipping a single occurrence of a repeating event.
Nothing is left half-done. If you close the tab or switch apps while the countdown is running, the delete is completed properly rather than being abandoned in an unclear state.
We built it this way, holding the delete back rather than deleting immediately and rebuilding the event afterwards, because rebuilding would create a new entry with a new identity, which quietly breaks links to a repeating series or anyone you had shared it with. Waiting a few seconds means the deletion simply never happens if you change your mind.