The + sign (plus sign or the New Record sign) in CRM Offline is not displaying to create Address or Child Account records in a Network Enabled Org.
DCR Field Types determine what fields are editable or require a DCR to modify. DCR or DCR_Required field types are required to allow a user to create a new record. They are required to allow a DCR to be created.
Include at least one DCR or DCR_Required field type for each object.
CRM Help Documentation: DCR Configuration