Please please please make it possible to add / delete parts and sub-asseblies in a positional representation.
For a user it makes zero sense that this is not the case. Software wize i can understand that there are enough exuses to dump this problem on users but "come on man" this is horrible.
When i select a part and press "delete" inventor simply plays deff.
While your at it, please make it possible to add a joint or constrain while i am in a positional representation.