Shared Mailbox Auto-Mapping in Exchange 2010

I have noticed- when we give a user member of group and we give that group rights to access another mailbox( shared Mailbox) it's not getting mapped in outlook, you have to to it manually- but if we give each user directly access to the shared mailbox- than Auto-mapping mailbox working fine

So if you want to use auto-mapping feature which is enabled by default you have to give each user directly rights on the mailbox indirectly auto-mapping won't work in Exchange 2010