Resources, new user, old user deleted

Try this:

Add resource as user Sabrina.
Delete user Sabrina without deleting the resource.
Change owner of resource with checkbox: [x] Send info ...

=> error message

I don't know if this is a problem with the resource manager, I guess it is a problem with the alert functions.

You may check what happens to an alert if the user who should get the alert does not exist anymore.

We could save this with a check inside RM, is this user existing => send alert
But better we check it in the alert function, right?