Prevent a crash when deleting objects accessed from a list of their abstract class (i.e. Select some Contacts, "delete...", select a Person, delete => crash).
Prevent a crash when deleting objects accessed from a list of their abstract class (i.e. Select some Contacts, "delete...", select a Person, delete => crash).

git-svn-id: 8a2b0a969c74f87a9c14cf35f460fb9b394f82c6@2420 a333f486-631f-4898-b8df-5754b55c2be0

changi67/itop,changi67/itop,changi67/itop,changi67/itop