VS20005 default intellisense recognizes enums and allows to easily access enum members when such a type is used. E.g. when using a contructor or member with an enum parameter. If that parameter should be entered VS2005 displays a completion box with he complete type. So pressing "." inserts the enum type followed by the "." and opens a new completion box which shows all enum members.
VAX disables this behavior. It would be nice to mimic the behavior as it speeds up entering the correct enum member quite a bit.