I have an application where the user can perform the following actions.
- Delete a project - Followed by a confirmation
- Rename a project
- Share a project
- Remove a shared user
For those actions, as feedback I can notify the user,
- The project has been deleted
- The project has been renamed
- The project has been shared with x,y,z users
- A X user has been removed from this project
I understand that something like an error message, e.g An error message for an invalid email address - is absolutely necessary because the user can't continue their work without addressing the issue. And it will work as it should on my app.
But is a success message always necessary if they can see a change has happened? (change being: after deleting the project - the project is no longer in there.)
[Edit]
The reason why I started wondering about this is, on mobile calendars, although the user is notified an event has been created, when an event is deleted it does not tell them it has been deleted. It is the same case when a contact is deleted as well.