Checkmk Werk 12860: Fix "element is not longer available" error on view edit

ID: 12860 Title: Fix "element is not longer available" error on view edit Component: Multisite Level: 1 Class: Bug fix Version: 2.1.0i1 Because of an empty grouping tooltip, the builtin views "hostnotifications", "hostsvcnotifications", "notifications", "failed_notifications", "svcnotifications", "contactnotifications" and "alerthandlers " showed an error "The selected element is not longer available. Please select something else." on edit.